PARIS — The office of a French satirical magazine here was badly damaged by a firebomb early on Wednesday, the publisher said, after it published a spoof issue “guest edited” by the Prophet Muhammad to salute the victory of an Islamist party in Tunisian elections. The publication also said hackers had disrupted its Web site.

The magazine, Charlie Hebdo, had announced a special issue for publication Wednesday, renamed “Charia Hebdo,” a play on the word in French for Shariah law.

The magazine’s editor, Stephane Charbonnier, told Europe 1 radio that the police had called just before 5 a.m. to report a fire of criminal origin. News reports said a Molotov cocktail had been thrown through a window. The special edition was on its way to the newsstands, the editor said, and will appear as scheduled.