The Franco-Russian billionaire, 39, was detained at Le Bourget airport north of the French capital on Saturday evening.

The Kremlin said Tuesday that France had levelled “very serious” charges against Telegram CEO Pavel Durov and warned Paris against trying to intimidate him, after the tech tycoon was arrested at a Paris airport last week.

French prosecutors accuse the 39-year-old billionaire of failing to curb the spread of illegal content on Telegram — charges his company denies.

French President Emmanuel Macron on Monday denied any political link to the arrest.

“The charges are indeed very serious, they require no less serious evidence. Otherwise this would be a direct attempt to restrict freedom of communication, and, I might even say, directly intimidate the head of a large company,” Kremlin spokesman Dmitry Peskov said.

“That is to say, precisely the policy that Mr Macron denied yesterday,” Peskov added.

Numerous questions have been raised about the timing and circumstances of Durov’s detention, which a source close to the case said had been extended until Wednesday.

Durov holds a French passport in addition to Russian nationality.

In its press information, Telegram says its founder has “dual citizenship of the United Arab Emirates (UAE) and France”.

The UAE said Tuesday It had requested consular services for the billionaire and was closely following his case. (AFP)