The Paris prosecutor’s office said on Friday it has opened a criminal investigation into X, the social-media platform owned by Elon Musk, on suspicions of data tampering and fraud. A specialised branch of the French gendarmerie is handling the inquiry. Prosecutors said the probe focuses on two potential offences: organised tampering with the functioning of an automated data-processing system and organised fraudulent extraction of data from such a system. The investigation targets both the platform and unidentified individuals believed to be involved. Authorities launched the case after receiving information in January from two people—a member of parliament and a senior public-sector official—who alleged that X’s algorithm was used for foreign interference. The prosecutor’s office said it decided this week to proceed after conducting its own checks and gathering additional material from researchers and public institutions. X has not commented on the investigation.