The lawyer for Telegram boss Pavel Durov said it was, "totally absurd to suggest that the head of a social network" such as his client could be involved in criminal acts, as the tech founder was granted bail in Paris but handed a travel ban.
"Telegram fully abides with European rules on digital. It is a moderator whose rules are similar to those of other social networks," David-Olivier Kaminski told several reporters.
A French judge put Durov under formal investigation on Wednesday in a probe into organised crime on the messaging app, but granted the entrepreneur bail on condition he pays five million euros (AED 20 million), reports twice a week to police and does not leave French territory.
Paris prosecutor Laure Beccuau said in a statement the judge found there were grounds to formally investigate Durov on all the charges for which he was arrested four days ago.
They include suspected complicity in running an online platform that allows illicit transactions, images of child sex abuse, drug trafficking and fraud, as well as the refusal to communicate information to authorities, money laundering and providing cryptographic services to criminals.
Durov's lawyer did not immediately respond to a Reuters request for comment.

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