French authorities have charged an 18-year-old suspected of participating in a major cyberattack against the country’s tax administration that exposed information belonging to 678,000 taxpayers.
The suspect, who reportedly uses the online alias “ChatNoir,” was arrested by France’s Anti-Cybercrime Office (OFAC) in the Paris region on August 18th. Two days later, he was formally placed under investigation and remanded in custody.
Investigators suspect the teenager of being connected to ZeroBytes, a hacking group that has claimed responsibility for attacks against several French government services and private organizations.
The case follows a breach of France’s General Directorate of Public Finances (DGFiP). Authorities previously confirmed that an attacker gained unauthorized access to its systems in late June through identity impersonation. The access was terminated, but not before information relating to individuals and businesses was viewed and extracted.
The DGFiP later determined that approximately 678,000 people were affected. Compromised information included identity and contact details, along with tax, income and property-related records. ZeroBytes has claimed that its access involved data concerning more than two million people, but French authorities have not confirmed that figure.
The 18-year-old faces multiple allegations, including unauthorized access to automated data-processing systems, extracting and possessing data, participation in a criminal conspiracy, and refusing to provide authorities with a cryptographic decryption secret. Some of the alleged offenses involve systems operated by the French state.
If convicted of the most serious charges, he could face up to ten years in prison and a €300,000 fine.
The suspect was already known to investigators. He had previously been charged in two separate cybercrime investigations involving alleged attacks committed in 2023 and 2024 while he was still a minor. He was under judicial supervision when arrested in connection with the DGFiP investigation.