Pavel Durov, the founder and CEO of the encrypted messaging app Telegram, was brought to court on Wednesday in Paris, according to media reports.
Durov's detention, which started on Saturday and was extended once, ended on Wednesday, broadcaster BFMTV said.
The investigating judge put an end to his custody in order to proceed to a preliminary examination and a possible indictment after the questioning, according to the broadcaster.
Durov was arrested on Saturday evening as he alighted from his private jet at Bourget Airport in Paris, according to French media outlets.
The 39-year-old Franco-Russian, listed as a wanted person in France, had just arrived from Azerbaijan.
After conducting a preliminary investigation, the French National Judicial Police issued his search warrant.
The investigation focused on Telegram's lack of moderation, which police believed enabled criminal activity to continue undeterred on the messaging app.
