Musk, the world's richest man, and former X chief executive Linda Yaccarino have been summoned for "voluntary interviews", while other employees of the platform are scheduled to be heard as witnesses throughout the week, the Paris prosecutor's office said.
It remains unclear whether Musk and Yaccarino will travel to Paris.
A spokesperson for X did not respond to questions from The Associated Press and Yaccarino's current company, eMed, did not respond to a request sent by email.
French prosecutors also suspect controversy around the platform's AI system Grok's deepfakes was concocted to boost the value of Musk-owned companies ahead of a key market listing, and alerted US authorities.
Musk welcomed a report that US justice officials refused to help French investigators, posting on X: "This needs to stop."
Musk was summoned after a search took place in February at the French premises of X as part of an investigation opened in January 2025 by the cybercrime unit of the Paris prosecutor's office.
Musk and Yaccarino have been invited in their capacities as managers of X at the time of the events being investigated.
Yaccarino was chief executive from May 2023 until July 2025.
"These voluntary interviews with the executives are intended to allow them to present their position regarding the facts and, where appropriate, the compliance measures they plan to implement," prosecutors said.
"At this stage, the conduct of this investigation is part of a constructive approach, with the ultimate objective of ensuring that platform X complies with French law, insofar as it operates within the national territory."
Asked whether Musk would risk sanctions if he skipped the hearing, the Paris prosecutor's office declined to comment.
French authorities opened their investigation after reports from a French lawmaker alleging biased algorithms on X likely distorted the functioning of an automated data-processing system.
It expanded after the AI system, Grok, generated posts that allegedly denied the Holocaust, a crime in France, and spread sexually explicit deepfakes.
It's looking into alleged "complicity" in possessing and spreading pornographic images of minors, sexually explicit deepfakes, denial of crimes against humanity and manipulation of an automated data processing system as part of an organised group, among other charges.
Grok, which was built by xAI and is available through X, sparked global outrage after it pumped out a torrent of sexualised non-consensual deepfake images in response to requests from X users.
Grok also wrote in a widely shared post in French that gas chambers at the Auschwitz-Birkenau death camp were designed for "disinfection with Zyklon B against typhus" rather than for mass murder - language long associated with Holocaust denial.
In later posts on X, the chatbot reversed itself and acknowledged its earlier reply was wrong, saying it had been deleted, and pointed to historical evidence that Zyklon B was used to kill more than one million people in Auschwitz gas chambers.
