The probe comes after comments made by Dieudonné during a December 19 performance, in which he referred to a Jewish radio journalist and quipped: "when I hear Patrick Cohen speak, I tell myself, you know, the gas chambers...shame [they no longer exist]."
French Interior Minister Manuel Valls has stated the comedian is "no longer a comedian" but rather an "anti-Semite and racist." Valls is weighing whether or not to ban all public appearances by Dieudonné.
Aside from the anti-Semitic comment, Dieudonné has coined his own gesture known as the "quenelle," a reversed Nazi salute in which one straightened arm is lowered while the other is folded across the shoulder. The comedian claims the salute is "anti-establishment", but critics say it is nothing short of anti-Semitic - particularly given Dieudonné's penchant for insulting Jews.
The Nazi salute has caught on with several public figures.
French soccer player Nicolas Anelka, a friend of Dieudonné, made the salute on Saturday after a match. Anelka denied the salute was spurred by anti-Semitism, claiming it was simply an anti-establishment gesture.
"This salute is merely a lesser known Nazi salute and we expect the same kind of punishment to be handed down by the authorities as if Anelka had made the infamous outstretched arm salute," said European Jewish Congress president Moshe Kantor in a statement. England's Football Association is considering taking action over the incident.
Similarly, French NBA star Tony Parker was caught on film making the salute during a TV interview. The Simon Wiesenthal Center has called on him to apologize.
Skyrocketing anti-Semitism in France has led to an increase in aliyah (emigration to Israel), accompanied by rising activity on the part of Jewish self-defense groups such as the French Jewish Defense League (LDJ).
The League recently made headlines after 6 Jewish youths, were arrested for identifying and beating up anti-Semites. Some reports suggested the attackers acting as part of the LDJ, but the group denied the claims.