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 had been arrested under a warrant for offences related to the popular messaging app.
Russia’s embassy in France is taking “immediate steps” to clarify the situation, according to Russia’s TASS state news agency.
Durov had been travelling on his private jet, French TV channel TF1 said on its website.
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.