Telegram chief executive Pavel Durov has been arrested by French police at an airport north of Paris.
Mr Durov was detained after his private jet had landed at Le Bourget Airport, French media reported.
According to officials the 39-year-old billionaire was arrested under a warrant for offences related to the popular messaging app.
The investigation is reportedly about a lack of moderators, with Durov accused of failing to take steps to curb criminal uses of Telegram.
Mr Durov was born in Russia and lives in Dubai. He holds dual citizenship of the United Arab Emirates and France.
Telegram is particularly popular in Russia, Ukraine and former Soviet Union states.
The app was banned in Russia in 2018, after a previous refusal by Mr Durov to hand over user data. But the ban was reversed in 2021.
Telegram is ranked as one of the major social media platforms after Facebook, YouTube, WhatsApp, Instagram, TikTok and Wechat.
Mr Durov founded Telegram in 2013 and he left Russia in 2014 after refusing to comply with government demands to shut down opposition communities on his VKontakte social media platform, which he sold.
Russian foreign ministry spokeswoman Maria Zakharova posted on Telegram asking whether Western human rights NGOs would be silent on Mr Durov’s arrest, after they criticised Russia’s decision to “create obstacles” to the work of Telegram in Russia in 2018.
Several Russian officials have condemned the businessman’s arrest.
X owner Elon Musk, who has faced extensive criticism over moderation and material hosted by his own social media site, posted repeatedly about the situation. He hashtagged one post #freepavel, and in another wrote: “POV: It’s 2030 in Europe and you’re being executed for liking a meme.”
