Investigators have raided the Paris offices of Elon Musk's social media site X, formerly known as Twitter.
French prosecutors said they were widening their probe into the platform and had summoned its billionaire owner for questioning.
Present and past employees, including former chief executive Linda Yaccarino, who left the company last year, were also summoned as witnesses.
The investigation, originally launched last month, will now cover the site's alleged complicity in the possession and distribution of child abuse images.
It also relates to allegations of sexual deepfakes, Holocaust denial, fraudulent data extraction and abuse of algorithms on the site.
The move follows complaints that Grok, the platform's AI chatbot, was being used to generate sexual photos of real women and children.
In a statement, the Paris prosecutor's office confirmed it had conducted a joint raid with the cybercrime unit of the French police and Europol.
Authorities were taking a "constructive approach", the statement said, "with the objective of ultimately ensuring the compliance of the X platform with French law".
It added that witnesses were being summoned voluntarily "to allow them to explain their position" and "the compliance measures they plan to implement".
The prosecutor's office also posted on X to confirm the raid, and added that it would be leaving the platform.
Last year, a Sky News investigation into algorithmic bias on X found that the platform was boosting right-wing and extreme content to users in the UK, regardless of the users' political leaning.
Read more:
The X Effect: How Elon Musk is boosting the British right
An X spokesperson told Sky News at the time of publication that eventually users will be able to adjust their feeds "dynamically", by asking X's AI tool Grok, which now powers the algorithm driving the platform's "For You" feed.
British regulatory watchdog Ofcom also opened a formal investigation into X last month under the UK's Online Safety Act to determine whether the firm was complying with its duties to protect people from illegal content.
A spokesperson for X did not immediately respond to a request for comment.
But Musk has previously accused French prosecutors of launching a "politically-motivated criminal investigation".
(c) Sky News 2026: French investigators raid Paris offices of Elon Musk's X
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