Prosecutors in Paris yesterday launched a probe into whether a French comedian was guilty of inciting racial hatred by joking about "gas chambers" while talking about a Jewish journalist.
Dieudonne, who has caused controversy over an increasingly copied trademark gesture that many view as a Nazi-style salute, is already facing a possible ban on public performances over anti-Semitic remarks.
The comedian maintains he is not anti-Jewish, and says the quenelle, his provocative downward version of a Nazi salute, merely reflects his anti-establishment views.
Judicial sources said the probe would centre around a December 19 performance by 47-year-old Dieudonne at a Paris theatre during which he mocked radio journalist Patrick Cohen, who is Jewish.
"When I hear Cohen speak, I tell myself, you know, the gas chambers ... Shame," he said.
Interior Minister Manuel Valls is threatening to ban all public appearances by Dieudonne, saying he is "no longer a comedian".
Valls said he was an "anti-Semite and racist" who had fallen foul of national laws against incitement to racial hatred.
Dieudonne, whose full name is Dieudonne M'Bala M'Bala, has been fined seven times for defamation, insult, hate speech and for racial discrimination.
He has described Holocaust remembrance ceremonies as "memorial pornography", made "Heil"-like signs on television as part of a sketch and befriended far-right leaders such as Jean-Marie Le Pen.
Dieudonne decries what he calls the "domination of Zionists" in Western societies and the overemphasis on the horrors of the Holocaust to the exclusion of other crimes, like slavery and racism.
Meanwhile his friend, the French striker Nicolas Anelka, is facing possible sanctions from the English Football Association after replicating the quenelle salute when he scored for his Premier League club West Bromwich Albion.
Anelka argued in tweets that the gesture - in which he thrust his straightened right arm downwards while tapping his bicep with the other hand - was merely "anti-establishment".
He insisted: "The meaning of quenelle is anti-system. I don't know what it has to do with religion."
Additional reporting by Reuters