Laurent Léger, an investigative journalist with Charlie Hebdo, shrugged off the idea, circulating on social media, that the cartoon contained one or even two hidden renderings of male genitals. “People can see what they want to see, but a cartoon is a cartoon,” he said. “It is not a photograph.”

Muslim leaders as far away as Egypt condemned Charlie Hebdo, recalling threats received by a Danish newspaper in 2005 after it, too, published cartoons satirizing Muhammad.

Elsa Ray, the spokeswoman of the Paris-based Collective Against Islamophobia in France, declined to react specifically to the new cartoon, but said that cartoons that lampooned Muhammad breached the limits of decency and insulted Muslims. “The freedom of expression may be guaranteed by the French Constitution, but there is a limit when it goes too far and turns into hatred, and stigmatization,” she said.

Moreover, she argued that the failure of French courts to clamp down on cartoons satirizing Muhammad was a double standard, given the robustness of action taken when Jews were insulted by cartoonists or artists, including Dieudonné M’bala M’bala, a comedian, who in 2013 came under the scrutiny of courts, which banned a series of his shows.

Mr. M’bala M’bala has said it was a shame that a Jewish journalist had not been killed in the gas chambers. He has also come under fire for popularizing a gesture that strongly resembles a Nazi salute.

In a statement on his Facebook page after Sunday’s enormous unity march in Paris, Mr. M’bala M’bala expressed his admiration for Amedy Coulibaly, the gunman behind the killings at a kosher supermarket. “As far as I am concerned, I feel I am Charlie Coulibaly,” he wrote, alluding to the “I am Charlie” rallying cry. The Paris prosecutor’s office said Monday it had opened an investigation to determine if Mr. M’bala M’bala should be charged with promoting terrorism.