French authorities are investigating a security incident involving Tchap, the French government’s encrypted messaging platform for civil servants, ministries, and public agencies. Multiple outlets report that the compromise is linked to an account hijacking, in which attackers take over a legitimate user account and then access public chat rooms on the platform. According to France’s Interministerial Directorate for Digital Affairs (DINUM), the breach occurs after a threat actor uses the hijacked account to gain access, rather than through a flaw disclosed as part of the report. Tchap is built on the open-source Matrix protocol and is intended to keep government communications on infrastructure managed by the French state. Engadget also notes that a threat actor has claimed responsibility for the attack, though specific details of the claim and the extent of impact are not fully described in the available reporting. The investigation is ongoing, and officials are assessing what data or communications were potentially exposed through the public rooms accessed by the attackers.