PARIS (AFP) - Paris City Hall on Wednesday decided to launch a lawsuit over reports by US news channel Fox News that there were "no-go zones" in the French capital that police and non-Muslims avoid.

In the wake of last month's attacks on Paris, Fox News aired reports, later widely derided, that suggested parts of the French capital and Britain's second city of Birmingham were run under Islamic Sharia law.

The City Hall will launch a suit "against persons unknown" for defamation.

City mayor Anne Hidalgo said: "I will not accept insults against our city and its people."

"What's in question here is not fun or... a bad joke, it's lies."

Fox broadcast a map outlining the so-called no-go zones, which a man labelled as an expert, Nolan Peterson, said felt like Afghanistan or Iraq.

A Fox news anchor later apologised for "some regrettable errors on air regarding the Muslim population in Europe, particularly with regard to England and France."

Asked last month about the prospect of a lawsuit, Fox News executive vice-president Michael Clemente said: "We empathise with the citizens of France as they go through a healing process and return to everyday life.

"However, we find the mayor's comments regarding a lawsuit misplaced."