"They’re into everything, from the Russian prostitute rings in resorts like Cannes and St Tropez to gassing tourists in their villa and stealing everything they’ve got," said the police officer.

"Bosses are now based here permanently, with foot soldiers working for them, often flying in for set periods before returning home with their profits in cash. The numbers really are unprecedented at the moment."

Alain Bauer, a French criminologist, said: "This is one of the best structured criminal organizations in Europe, with a quasi-military operation".

Another investigator, from the judicial police in Nice, told Le Figaro newspaper that he had recently been involved in the arrests of two eastern Mafia chiefs.

"One of them is involved in a vast money laundering operation in Spain and waiting to be extradited", said the officer. "The other is suspected of masterminding the assassination of another rogue Georgian, and he organized a very violent settling of accounts, worthy of an action film, in a flat in Nice."

Laurent Laubry, a representative of the police union Alliance, said that many of the gang members were heavily armed ex-soldiers from Soviet regions such as Chechnya.

He said that one of his colleagues was beaten up by four Chechens as he went to buy a packet of cigarettes last week.

"The undercover officer received a rain of blows to the face and was left for dead between two cars," said Mr Laubry, who described the "ultra-violent methods of these people, who have no morals, no rules, and who are often heavily armed and beefy."

After a decade on the run, Sicilian Godfather Giuseppe Falsone, was arrested in June, in Marseilles after a decade on the run. He was believed to have had plastic surgery and was using false identification while continuing to coordinate criminal activity, said local police.     Add Comments>>