BBC:
Telegram boss and founder Pavel Durov has been placed under formal investigation in France as part of a probe into organised crime on the messaging app, Paris prosecutors say.
Mr Durov, 39, has not been remanded in custody, but placed under judicial supervision, and has to pay a €5m (£4.2m; $5.6m) deposit.
The Russian-born billionaire, who is also a French national, also has to show up at a French police station twice a week and is not allowed to leave French territory.
Mr Durov was first detained upon arrival at Le Bourget airport north of Paris last Saturday under a warrant for offences related to the app.
