The Paris prosecutor’s office has opened an ⁠investigation into ⁠a 15-year-old, suspected of having ⁠hacked the country’s ID agency and trying to sell the data of millions of French people on the dark web this month, it said on Thursday.

The teenager, whose identity ‌was not revealed, was detained on April 25 and held in police custody for questioning after he was suspected of hiding behind the nickname “breach3d”, a hacker who had put on sale on hacker forums between 12 million and 18 million...