The offices of the French satirical magazine Charlie Hebdo have been destroyed by a petrol bomb, French police say.
It comes a day after the publication named the Prophet Muhammad as its “editor-in-chief” for its next issue.
Its cover carried a caricature of the Prophet making a facetious comment.
The magazine said the move was intended to “celebrate” the victory of an Islamist party in last month’s Tunisian elections.
Charlie Hebdo’s editor is quoted as saying: “We no longer have a newspaper. All our equipment has been destroyed.”
A witness at the scene, Patrick Pelloux, told AFP news agency that a Molotov cocktail was hurled through an office window and that it set fire to the computer system.
“Everything was destroyed,” he said.
There have been no reports of injuries.
Charlie Hebdo’s website has also been hacked with a message in English and Turkish attacking the magazine.
The edition of the paper which was being published on Wednesday was called Charia Hebdo – a play on the Islamic word sharia.
The cover shows Muhammad saying : “100 lashes if you are not dying of laughter”.
Inside there is an editorial, attributed to the Prophet, and more cartoons – one showing the Prophet Muhammad with a clown’s red nose.
Depiction of the Prophet is strictly prohibited in Islam.
In a statement on Tuesday, the magazine said it was motivated by the recent victory of the Islamist Ennadha party in elections in Tunisia, and by indications that sharia law could form the basis of legislation in post-Gaddafi Libya.
The magazine denied it was trying to be provocative.
On Tuesday the publication’s editor-in-chief and cartoonist Charb told AFP: “We don’t feel like causing further provocation. We simply feel like doing our job as usual. The only difference this week is that Muhammad is on the cover and it’s pretty rare to put him on the cover.”
In 2007, Charlie Hebdo reprinted 12 controversial cartoons of the Prophet Muhammad that were first shown in a Danish newspaper, Jyllands-Posten, and caused outrage in the Muslim world.
The magazine was sued for incitement to racism by two Islamic groups in France, but was acquitted by a Paris court.
A BBC correspondent in France, Hugh Schofield, says Charlie Hebdo has a long track record of irreverence to all religions.