Data Breach Alert: Step-by-Step Guide on How to Respond Effectively

On August 13, 2026, the General Directorate of Public Finances confirmed unauthorized access to its information system that occurred at the end of June following identity theft, leading to the extraction of data belonging to individuals and professionals. The press release from Bercy stated that the extracted data pertained to both individuals and professionals, thereby widening the circle of affected parties to include entities that interact with the tax administration. Whether the leak affects a government or a private entity, the immediate steps to take vary depending on the type of information exposed (passwords, IBANs, or identity documents). Let’s delve into the details.

What steps should one take to prevent data leaks?

Several precautions can help minimize the impact of a data breach before it happens. Cybermalveillance.gouv.fr advises only sharing the minimum necessary information during online registrations, avoiding the transfer of identity documents without precautions, and not saving banking details for one-off purchases. Using a unique password for each service, combined with a password manager and two-factor authentication where available, reduces the risk that a compromised account could lead to further unauthorized access to other accounts using the same password.

Deleting accounts and applications you no longer use is another effective measure to protect yourself and reduce the exposure in case of a breach at a third-party provider. When sending an identity document, using a free tool like FiligraneFacile can add a personalized watermark to the document before its transmission, helping to prevent misuse in the event of a subsequent leak.

How should one respond depending on the type of data compromised?

Once a data breach is confirmed, the appropriate response depends on the type of data exposed, with the timing of the response often being more critical than the nature of the service affected:

• Password: immediately change it for the service affected, prioritizing sensitive accounts (email, bank, taxes), and avoid reusing it on other sites.
• Bank details or IBAN: monitor transactions on your account and request reimbursement from your bank for any unauthorized transactions. Do not hesitate to block your card if necessary and inform the institution of the leak to increase vigilance on the affected account.
• Identity document: it’s advisable to check with the Bank of France if there are any incidents of non-repayment of loans registered in your name, and to consult the FICOBA file from your area on the tax website to ensure that no accounts have been fraudulently opened.

How can one identify and avoid scams following a data breach?

A personal data breach often leads to a surge in phishing attempts, which use the stolen information to appear legitimate. If your data has been compromised, the CNIL advises never to click on a link or respond to a message from a sender claiming to have this information, and to always use the official website of the concerned service instead. Cybermalveillance.gouv.fr also warns about the scenario of a fake bank advisor, or even a fake courier coming to retrieve a bank card at home under the guise of fraud.

In all cases, verifying the identity of the contact should be done using the official contact details of the organization, never those provided in the received message. If personal information is found spread across a social network or a search engine, it can be reported directly to the concerned platform to request its removal.