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Policy

Training Data Privacy: GDPR Data Subject Rights

EDPB Opinion 28/2024 and CNIL guidance reshaped how GDPR applies to AI training data, from model anonymity to legitimate interest and erasure requests.

By AI Privacy Report Editorial · ·Updated · 16 min read

Under the GDPR, people in an AI training set keep their rights to information, access, rectification, erasure, restriction and objection, over the dataset and the model unless it is shown to be anonymous. Regulators accept a layered response: delete from the corpus, exclude from the next training run, test for memorization, and filter outputs where retraining is disproportionate.

Two points are still contested: whether a trained model holds personal data at all (the EDPB says test case by case; the Hamburg DPA said no in 2024), and whether blocking an output cures an inaccurate one, the question in noyb’s complaints against OpenAI. Lawful basis, processing records and vendor diligence are covered in GDPR compliance for machine learning models; this page is the request-handling reference.

Which rights apply to which copy of the data

A request about “my data in your AI” can land in four places: the raw corpus, the fine-tuning set (often reused chat transcripts, the default consumer assistants moved to in 2025), the model weights, and the outputs and logs. The legal text is the same for all four; the feasible response is not. The CNIL recommends telling requesters whether you read the request as aimed at the training data or the model, and how you are answering it.

How each right applies at each layer

RightRaw corpusFine-tune setModel weightsOutputs and logs
Information (Art. 13, 14)Art. 14, within one month; public notice if individual notice is disproportionate (Art. 14(5)(b))Art. 13 if collected from the person; notice before reuse for training (Art. 13(3))Disclose the regurgitation risk, safeguards and redress routeExplain how to report outputs containing personal data
Access (Art. 15)Copy of the person’s records, annotations, metadata and available source, redacting other people’s data (Art. 15(4))Same, including labels and feedbackMemorization check results with example outputs, or “not impossible” if inconclusiveLogged prompts and outputs about the person
Rectification (Art. 16)Correct records and annotationsCorrect, then retrain the adapterNo direct edit: retrain, or filter until the next training runThe main battleground: false statements about real people
Erasure (Art. 17)Delete, add to the exclusion list, notify recipients (Art. 19)Delete, then retrain the adapterRetrain where proportionate, robust filter until then; Art. 17(3) exceptions applyDelete logs; filter regeneration
Restriction (Art. 18)Quarantine, storage only, while accuracy or an objection is checkedHold out of the next runBlock outputs about the person during the checkSuppress during the check
Objection (Art. 21)Stop unless you show compelling legitimate grounds; offer an opt-out before collectionHonor before the next runBites on the next run and on outputsSuppress outputs about the person
Identification (Art. 11, 12(2))If you demonstrate you cannot identify the person, Articles 15 to 20 fall away unless they supply extra informationSameAsk for the prompts that surface the dataSame

What regulators have accepted

RightAccepted or signaled responsePrimary source
InformationA public, layered notice (a dataset or model card works if it stands out) naming sources, or at least the riskiest source categories, published before trainingCNIL informing sheet; EDPB Guidelines 03/2026 (draft); GDPR Art. 13, 14
AccessTraining-record copies plus the memorization investigation; withheld data, sources and recipients are one ground of noyb’s April 2024 complaintCNIL rights sheet; GDPR Art. 15
RectificationRetraining, which can be batched, or robust filters; whether prompt-level blocking cures inaccurate outputs is before regulators in both noyb complaintsCNIL rights sheet; GDPR Art. 16
ErasureThe same toolkit; refusal only in narrow cases such as the CNIL’s public-figure example; unlearning only once it can guarantee deletionCNIL rights sheet; EDPB Guidelines 03/2026 (draft); GDPR Art. 17
RestrictionNo AI-specific regulator guidance yet; apply the text and log the holdGDPR Art. 18
ObjectionA route open before any training begins; if you call the opt-out unconditional, honor it automatically. Meta kept its form open for over a yearIrish DPC AI Insights Report; DPC statement on Meta; GDPR Art. 21
IdentificationSay in the notice that you cannot identify people, and what extra information would let you actCNIL informing and rights sheets; GDPR Art. 11, 12(2)

Article 17(3) exceptions are narrow (expression and information, legal obligations and public-interest tasks, public health, archiving, research or statistics that erasure would seriously impair, legal claims), and “retraining is expensive” is not one of them; the CNIL treats cost and complexity as proportionality factors. Its examples mark the range: a public figure asking to be erased from a model that correctly reports public figures’ roles, where retraining is very costly, may in principle be refused; a non-anonymous insurance model that surfaces one claimant’s settlement obliges the controller to propose a solution. Where outputs drive decisions about a person, Article 22 adds rights of its own.

The threshold question: is the model personal data?

Only if it fails the EDPB’s anonymity test, and the controller must be able to demonstrate that it passes. Opinion 28/2024, adopted on 17 December 2024 at the Irish DPC’s request, treats a model as anonymous only where it is “very unlikely” both to identify, directly or indirectly, the people whose data trained it and to let anyone extract that data through queries. Supervisory authorities judge that case by case, weighing tests for membership and attribute inference, exfiltration, regurgitation, model inversion and reconstruction. Legitimate interest as a training basis (the EDPB’s three-step test) and the processing record each stage needs are covered in GDPR compliance for machine learning models; how a claimed anonymization is judged, in pseudonymization versus anonymization under GDPR. The CNIL asks developers to prioritize anonymizing training data; federated learning is the architectural alternative that avoids pooling it at all.

What the CNIL’s February 2025 recommendations say

The CNIL’s recommendations of 7 February 2025, on informing data subjects and on facilitating their rights, are where the output-filtering practice comes from, and they attach more conditions to it than the shorthand does.

Notice

  • Individual notice applies where you hold contact details and reaching people is not disproportionate. Otherwise a public notice under Article 14(5)(b) suffices, provided you document the disproportion and take appropriate measures such as a DPIA even where Article 35 does not require one.
  • Name sources precisely when they are few. When they are many, categories or a few main sources generally suffice; for scraping, the categories of sites, at least the riskiest. Domain names, URLs and collection dates are good practice, not a requirement.
  • As good practice, leave a reasonable period between notice and training. Model and dataset cards can carry the notice if it stands out; a specialist technical paper cannot.

Rights

  • You need not keep identifiers just to answer requests. People can supply extra information, such as an image or a pseudonym, and an LLM developer can ask for the prompts the requester believes reveal memorization. If you still hold the training data, find the person there first, then check the model.
  • Retraining is the primary remedy while you hold the data, and it can run periodically to clear several requests at once. Ship the updated model and, as good practice, contractually require downstream users to run current versions.
  • Filters are acceptable when retraining is disproportionate, or “pending the next training” when it cannot happen within the response deadline, if they are “sufficiently effective and robust (i.e. they cannot be circumvented)”. The CNIL prefers general rules that stop the system generating personal data, such as named-entity recognition, over a blacklist of people who exercised their rights; a blacklist must be secured and assessed for the membership inference risk it adds.

The CNIL’s June 2025 legitimate-interest recommendations and web-scraping focus sheet list the collection-side measures, mandatory and recommended: define collection criteria in advance, exclude unnecessary categories and delete irrelevant data at once, skip sites that object through robots.txt or CAPTCHA, keep a default exclusion list of sensitive sites such as health forums, offer a discretionary right to object before collection, and pseudonymize or anonymize promptly. A scraper built that way already has the exclusion list an erasure request needs.

Decision procedure: route each request by where the data sits

Record the reasoning at every branch in the DPIA (the DPIA template for LLM deployment gives a structure).

Where the data sitsActionRecord
Raw corpus and derived datasetsDelete; add URLs, identifiers and document hashes to the exclusion list the next crawl and dataset build read; notify recipients of copies; if you published the dataset, take reasonable steps to tell controllers processing it (Art. 17(2))Hits, deletion date, exclusion entry
Fine-tuning or adapter dataDelete, retrain the adapter and ship it; an adapter costs far less to retrain than a base model, which weakens any disproportion argumentAdapter versions before and after
Retrieval index, prompt logs, stored outputsDelete like any database record; re-indexDeletion date
Base weights you trainedAssess extractability (worked example below). Extractable: robust output filter now, excluded from the next retrain. Not extractable: say so, with the “not impossible” caveat where it appliesProbe log, filter test, retrain date, and the ground for not retraining now: an Art. 17(3) exception, Art. 12(5) for a manifestly unfounded or excessive request, or cost-and-complexity proportionality
Third-party base modelThe provider is the controller for its training data: name it and how to reach it, forward the request if your contract provides for that, and handle your own layersProvider, date forwarded, what you handled

“Not our model” is an incomplete answer on the third-party branch: the prompts, logs, retrieval index and filter are yours, and any part you decline needs a reply within one month with reasons and the complaint route (Art. 12(4)). The CNIL draws the same line for knowledge bases: requests about one a third party added go to that third party. Provider diligence questions are in GDPR compliance for machine learning models, and forwarding to a provider outside the EEA is a transfer (cross-border LLM data transfers).

Worked example: erasure against a model trained on scraped web data

A company pre-trains its own model on a web crawl, adds an adapter fine-tuned on support transcripts, and serves it with a retrieval index. A private individual writes in: asked about them by name, the assistant returns their street and employer. They want it all erased.

  1. Day 0: log and scope. Log receipt; Article 12(3) gives one month. Acknowledge, say you are treating the request as covering the training data and the model, and ask for name variants, usernames, URLs where the data appeared and the prompts that surfaced it. Ask for identity proof only if you have reasonable doubts (Art. 12(6)). A request-tracking platform keeps the clock.
  2. Days 1 to 5: search. Search the retained crawl and every derived artifact (deduplicated shards, tokenized caches, the fine-tune set, the retrieval index) for the identifiers and URLs, and record document IDs, source URLs and crawl dates. If the crawl was not kept, record that; Article 11 then shapes the answer.
  3. Days 5 to 10: delete and exclude. Delete matching documents and chunks, purge logs, add URLs, identifiers and document hashes to the exclusion list, retrain the adapter if the transcripts contained the person, and notify recipients of dataset copies.
  4. Days 5 to 15: test the weights. Deletion does not touch a trained model, and Carlini et al. extracted names, phone numbers and email addresses from GPT-2, including sequences that appeared in a single training document. Run this yourself and keep the log:
    • Pin the model version (record the weights hash) and run every probe with production filters off, then on.
    • Build three probe sets: prefix probes (the text just before the person’s data in each deleted document, for the model to continue), direct questions (“Where does [name] live?”, “Who employs [name]?”), and the requester’s own prompts.
    • Use greedy decoding plus repeated sampling at a non-zero temperature, for example 20 samples at 1.0, and record the settings so the next model gets the same test.
    • Run the direct questions for several fictitious names of the same form as controls.
    • Read the results. A verbatim continuation of a corpus prefix is memorized, extractable text; memorization grows with model capacity, duplication and prompt length (Carlini et al., 2022). Attributes that appear for the real name but not the controls point to memorization; attributes invented for the controls too suggest generation from correlations, as the CNIL warns, and a false statement is then a rectification issue. Membership inference testing adds a statistical check if you can train shadow models.
  5. Days 15 to 25: choose the model-level remedy. If a retrain that excludes the documents lands inside the deadline, use it and tell downstream users to update. Otherwise filter pending the next training with a general rule (no home addresses or employers for private individuals) rather than a list of complainants, and rerun the probes with the filter on, plus paraphrases and other languages, to show it cannot be circumvented. Record the results, the retrain date and why you are not retraining now.
  6. Within one month: respond or extend. If testing or the retrain date is unsettled, notify an extension of up to two further months, with reasons, before the first month ends. Anything you decline needs reasons plus the complaint and court routes (Art. 12(4)).

The weights paragraph should state what erasure did and did not do, without overclaiming (“your data has been deleted from our AI”):

[Controller] found [N] documents containing your name, street and employer in its training corpus. They have been deleted from the corpus and every dataset derived from it, and their URLs and your identifiers are on the exclusion list for all future collection and training. The model in service, [model version], was trained before your request, and deleting source documents does not change a trained model. Queried with [N] prompts, including yours, it reproduced your street name in [n] outputs; examples are attached. Since [date], a filter has stopped the service generating home addresses and employer details for private individuals, and the next model, due [date], is being trained without your data. Until it replaces the current one, the filter, not the model, is what prevents disclosure. If your data appears in any output, send the prompt and it will be handled as a new request. You can also complain to [supervisory authority].

Models built on unlawfully processed data: the three EDPB scenarios

Opinion 28/2024 does not say unlawful training automatically taints deployment. It sets out three scenarios:

ScenarioWhat the EDPB saysWhat it means for a deployer
1. Personal data retained in the model; the same controller deploysWhether development and deployment are separate purposes, and how far the missing legal basis affects deployment, is decided case by caseNo clean break: a developer deploying its own model should expect both phases to be examined together
2. Personal data retained; another controller deploysAuthorities consider whether the deployer made an appropriate assessment, as part of its accountability, that the model was not developed unlawfully, looking at the data’s source and any infringement finding by an authority or court, scaled to deployment riskExposure turns on documented diligence about the provider’s sources and any findings against it
3. Model anonymized before the same or another controller deploysIf operating the model involves no personal data, the GDPR does not apply and the unlawful training should not affect its operation; personal data processed in deployment is under the GDPR in its own rightOnly as strong as the anonymity evidence: get the provider’s extraction and inference test results, or you are back in Scenario 2

Findings move, so a Scenario 2 assessment needs rechecking. The Garante’s December 2024 decision that OpenAI trained ChatGPT without first identifying an appropriate legal basis was the kind of finding Scenario 2 names, until the Tribunale di Roma annulled it on competence grounds in March 2026 without examining the merits.

Enforcement and case record

DateBodyWhat happenedWhy it matters
29 Apr 2024noyb to Austria’s DSBChatGPT kept giving a public figure a wrong birth date; OpenAI said it could block data on prompts such as their name but not correct it, and did not adequately answer their access requestFirst test of rectification and access against a model provider; still pending
Jul 2024Hamburg DPADiscussion paper: no personal data is stored in an LLM, so storing one is not processing; rights attach to the AI system’s inputs and outputs; training violations do not make later use unlawfulThe opposing view to EDPB 28/2024
20 Dec 2024Garante€15 million fine on OpenAI (decision 755 of 2 Nov 2024): training without an identified legal basis, transparency failures, no age verification, an unreported March 2023 breach, plus a six-month campaign on objecting, rectification and erasureAnnulled by the Tribunale di Roma on 18 Mar 2026: the Irish DPC had become lead authority on 15 Feb 2024; the merits were not examined
20 Mar 2025noyb to Norway’s DatatilsynetChatGPT falsely described a Norwegian man as having murdered two of his children; noyb seeks deletion of the output, fine-tuning to remove inaccurate results, and a fineIrish DPC lead since 30 Jun 2025; tests whether blocking outputs suffices while the model may still hold the data
14 Apr to 27 May 2025Meta; Irish DPCMeta notified EU users and opened an objection form before training on adults’ public content began on 27 May; the DPC cited a longer notice period, in-app forms open over a year, de-identification and output filtersThe objection-before-training model regulators have accepted
23 May 2025OLG Köln, 15 UKl 2/25Refused Verbraucherzentrale NRW’s injunction; legitimate interest accepted, citing EDPB 28/2024; about six weeks to object held adequateReasonable expectation of AI training ran only from Meta’s 10 Jun 2024 announcement, yet the safeguards carried the balancing
8 Jul 2026EDPBGuidelines 03/2026 on web scraping for generative AI, open for comment until 30 Oct 2026Public notice mandatory when relying on Art. 14(5)(b); data “cannot be easily deleted” from a trained model; unlearning only once it can guarantee deletion
25 Sep 2026Irish DPCAI Insights Report on its 2021 to 2025 supervisionObjection must be available “before any AI training begins”; “if your objection is honoured” misleads where the opt-out is unconditional

The objection row may change by statute. The Commission’s Digital Omnibus proposal of 19 November 2025 would add an Article 88c confirming that developing and operating AI can rest on legitimate interest, with an unconditional right to object. EDPB-EDPS Joint Opinion 2/2026 replied that legitimate interest is already available and the right belongs in Article 21, flagged well in advance because retained data can be hard to remove. The Council compromise 12535/26 of 3 September 2026, published by noyb, reportedly drops that right from the operative text. Nothing has been adopted.

FAQ

Can I get my personal data removed from an AI model?

Yes: if the model is not anonymous, erasure and objection apply. Expect the developer to delete your data from its training set, keep it out of the next training run and block outputs about you, rather than retrain at once; regulators accept that where retraining is disproportionate. If the answer falls short, complain to your supervisory authority.

Is machine unlearning required for GDPR erasure?

No. Neither the CNIL nor the EDPB requires it. The CNIL accepts retraining, which can be batched periodically, or robust output filters when retraining is disproportionate. The EDPB’s draft web-scraping guidelines say unlearning could replace filters or retraining once an algorithm can guarantee that specific data has actually been deleted from the model.

Does the right to object still apply after my data was used for training?

Yes. Article 21 applies at any time to processing based on legitimate interest, and the controller must stop unless it shows compelling legitimate grounds. After training, an objection mostly bites on the next training run and on outputs, which is why the Irish DPC wants the objection route open before any training begins.

Sources

  1. EDPB Opinion 28/2024 on AI models and personal data
  2. CNIL — Legitimate interest: web scraping focus sheet
  3. GDPR Article 17 — Right to erasure
  4. EDPB Opinion 28/2024, full text (adopted 17 December 2024)
  5. EDPB press release: EDPB opinion on AI models, GDPR principles support responsible AI (18 December 2024)
  6. CNIL: AI and GDPR, the CNIL publishes new recommendations to support responsible innovation (7 February 2025)
  7. CNIL: Informing data subjects (AI system development recommendations)
  8. CNIL: Ensuring and facilitating the exercise of data subjects' rights (AI system development recommendations)
  9. CNIL: Développement des systèmes d'IA, la CNIL publie ses recommandations sur l'intérêt légitime (19 June 2025)
  10. GDPR Article 11: Processing which does not require identification
  11. GDPR Article 12: Transparent information, communication and modalities for the exercise of rights
  12. GDPR Article 13: Information to be provided where data are collected from the data subject
  13. GDPR Article 14: Information to be provided where data have not been obtained from the data subject
  14. GDPR Article 15: Right of access by the data subject
  15. GDPR Article 16: Right to rectification
  16. GDPR Article 18: Right to restriction of processing
  17. GDPR Article 19: Notification obligation regarding rectification or erasure or restriction
  18. GDPR Article 21: Right to object
  19. EDPB Guidelines 03/2026 on web scraping in the context of generative AI, version 1.0 (public consultation draft)
  20. EDPB public consultation on Guidelines 03/2026 (8 July to 30 October 2026)
  21. Irish DPC: Data Protection Commission publishes AI Insights Report (25 September 2026)
  22. Irish DPC: Responsible Artificial Intelligence Innovation, insights from the DPC's supervision of AI (2021-2025)
  23. Irish DPC: DPC statement on Meta AI (21 May 2025)
  24. Meta: Making AI Work Harder for Europeans (14 April 2025)
  25. OLG Köln, judgment of 23 May 2025, 15 UKl 2/25 (Verbraucherzentrale NRW v Meta)
  26. Garante privacy: ChatGPT, il Garante privacy chiude l'istruttoria (press release, 20 December 2024)
  27. Tribunale di Roma, judgment of 18 March 2026, R.G. 4785/2025 (OpenAI OpCo v Garante)
  28. European Law Blog: Establish, then escape? The Court of Rome, the one-stop-shop and an AI enforcement gap
  29. noyb: ChatGPT provides false information about people, and OpenAI can't correct it (29 April 2024)
  30. noyb case C078: OpenAI OpCo, LLC (Austrian complaint)
  31. noyb: AI hallucinations, ChatGPT created a fake child murderer (20 March 2025)
  32. noyb case C097: OpenAI OpCo, LLC (Norwegian complaint)
  33. Hamburg Commissioner for Data Protection: Discussion Paper, Large Language Models and Personal Data (July 2024)
  34. EDPB-EDPS Joint Opinion 2/2026 on the Digital Omnibus proposal
  35. noyb: EU Member States plan digital expropriation of Europeans in the interest of AI companies (21 September 2026)
  36. PPC Land: EU Council draft drops unconditional opt-out from GDPR AI clause (21 September 2026)
  37. Carlini et al.: Extracting Training Data from Large Language Models
  38. Carlini et al.: Quantifying Memorization Across Neural Language Models
#gdpr #training-data #edpb#cnil#right-to-erasure#legitimate-interest #compliance
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