Art. 34 GDPR · Chapter IV: Controller and processor · Section 2: Security of personal data
Article 34 GDPR: Communication of a personal data breach to the data subject
Text as of 28 October 2026 Reviewed by Sergio Maldonado Elvira on 29 October 2026
Summary (not the official text)
When a personal data breach is likely to result in a high risk to the rights and freedoms of natural persons, the controller must communicate it to the data subject without undue delay, in clear and plain language. Paragraph 3 lists the cases in which this communication is not required.
Official text
When the personal data breach is likely to result in a high risk to the rights and freedoms of natural persons, the controller shall communicate the personal data breach to the data subject without undue delay.
The communication to the data subject referred to in paragraph 1 of this Article shall describe in clear and plain language the nature of the personal data breach and contain at least the information and measures referred to in points (b), (c) and (d) of Article 33(3).
The communication to the data subject referred to in paragraph 1 shall not be required if any of the following conditions are met:
the controller has implemented appropriate technical and organisational protection measures, and those measures were applied to the personal data affected by the personal data breach, in particular those that render the personal data unintelligible to any person who is not authorised to access it, such as encryption;
the controller has taken subsequent measures which ensure that the high risk to the rights and freedoms of data subjects referred to in paragraph 1 is no longer likely to materialise;
it would involve disproportionate effort. In such a case, there shall instead be a public communication or similar measure whereby the data subjects are informed in an equally effective manner.
If the controller has not already communicated the personal data breach to the data subject, the supervisory authority, having considered the likelihood of the personal data breach resulting in a high risk, may require it to do so or may decide that any of the conditions referred to in paragraph 3 are met.
Source: Regulation (EU) 2016/679, Official Journal L 119, 4.5.2016, as corrected. Only the text published in the Official Journal is authentic. © European Union, https://eur-lex.europa.eu
Text as of 28 October 2026.
This is reference material, not legal advice.
Related recitals
This list is under review.
EDPB guidance
- Guidelines 9/2022 on personal data breach notification under GDPR
EDPB 09/2022FinalFirst published 18 October 2022Final version 4 April 2023
Targeted update of WP29 WP250 rev.01, which it supersedes.
- Guidelines 01/2021 on examples regarding personal data breach notification
EDPB 01/2021FinalFirst published 19 January 2021Final version 3 January 2022
Final date is the EDPB publication date of version 2.0.
Fines
Amounts are shown in the currency in which the fine was imposed.
- FREE MOBILE: EUR 27,000,000
Commission nationale de l'informatique et des libertés (CNIL), FranceDecision of 8 January 2026Appeal status: unknown
After an October 2024 intrusion exposed 24 million subscriber contracts (including IBANs): weak VPN authentication and poor detection, an incomplete breach notice to subscribers, and excessive retention of former subscribers' data.