Cardinal Jean-Marie Lustiger, archbishop of Paris; Grand Rabbi Joseph Sitruck of France, and rector Dalil Boubaker of the Grand Mosque of Paris, encouraged believers to remain "calm" for fear that the conflict would unleash a "war of religions."

"We must maintain the republican tradition of tolerance and respect for all. It is not necessary to add, in such a tense international situation, a deterioration of the social climate," the three religious leaders said.

Their appeal sought to avoid, among other things, the attacks launched last year at the height of the Israeli-Palestinian conflict, against the Jewish community in France, which numbers some 700,000 people.