The French comedy circuit is in crisis after a mystery online whistleblower shamed some of the country's best-know stand-ups to admit they had stolen their jokes from their British and American counterparts.

Millions have tuned into anonymously posted CopyComic videos of household French names apparently brazenly plagiarising the likes of Lee Evans, Robin Williams and Jerry Seinfeld.

In some cases they merely translate word for word the gags while passing them off as original material.

Among those upbraided for plagiarism is Jamel Debbouze, a wildly popular comedian who is known in the UK for his serious part in the film Days of Glory.

Debbouze can be seen copying Dave Cappelle, the American comedian and using the same gestures from a 2000 show.

Another alleged repeat copycat is Gad Elmaleh, who was married to Princess Charlotte of Monaco and now has a successful career over in the US. In one montage, he can be seen aping George Carlin, the American comedian, from a 1996 sketch.

The first to be outed was French star Tomer Sisley. An implacable eight-minute Youtube video showed how he lifted jokes from a string of American comedians. He later admitted to having copied between “20-30 per cent” of his gags.