A Russian-French billionaire who founded the popular messaging app Telegram was arrested on Saturday evening at Bourget airport near Paris, according to reports.
Tech mogul Pavel Durov, 39, was reportedly leaving his private jet when he was detained.
French media outlets claim Durov was the subject of a French arrest warrant linked to a preliminary police investigation.
Both TF1 and BFM TV claim that the investigation centres on Telegram's alleged lack of moderators, which authorities believe has allowed criminal activity to flourish unchecked on the platform.
French media suggest Durov could face indictment as early as Sunday.
Telegram, boasting nearly a billion users worldwide, is particularly influential across the former Soviet Union. It ranks among the top social media platforms globally, alongside the likes of Facebook and WhatsApp.
When approached for comment, Telegram did not immediately respond. The French Interior Ministry and police declined to comment on the matter.
Durov, born in Russia, established Telegram with his brother in 2013. He left his homeland in 2014 after refusing to bow to government pressure to shut down opposition groups on VKontakte, the social media platform he had previously created and subsequently sold.
"I would rather be free than to take orders from anyone," Durov told American journalist Tucker Carlson in April, explaining his departure from Russia and his company's nomadic existence, which has included stints in Berlin, London, Singapore and San Francisco.
Since Russia's invasion of Ukraine in 2022, Telegram has become a primary source of unfiltered - and at times graphic and misleading - content about the conflict from both sides. Analysts have dubbed it 'a virtual battlefield' for the war, used extensively by Ukrainian President Volodymyr Zelensky and his officials, as well as the Russian government.
The platform's ability to evade official scrutiny has also made it one of the few remaining avenues for Russians to access independent news about the war, following the Kremlin's crackdown on independent media in the wake of the invasion.
The Russian foreign ministry said its embassy in Paris was seeking clarification on Durov's situation and called on Western NGOs to demand his release.
Russia had previously attempted to block Telegram in 2018 after the app refused to grant state security services access to users' encrypted messages. The ban, which proved largely ineffective, sparked mass protests in Moscow and criticism from NGOs.