France enforced a ban on gatherings that could cause trouble in Paris on Saturday and thousands of police patrolled the capital to prevent urban violence reaching the heart of the city.
The unrest has fallen in intensity since President Jacques Chirac's government announced emergency measures on Tuesday including curfews to curb the rioting by youngsters angered by unemployment, racism and lack of opportunities.
But the number of cars set ablaze by rioters rose again slightly on Friday night, the 16th night of violence, and two fire bombs were thrown at a mosque in southern France, slightly damaging the entrance.
Some 502 vehicles were set ablaze across France, compared to 463 the previous night, and unrest hit areas including Strasbourg, Marseille, Lyon and Lille. But there were fewer incidents of violence in the Paris suburbs, police said.
"We've gone back to an almost normal situation in Ile de France (greater Paris region)," national police service chief Michel Gaudin told reporters.
The Paris ban went into force at 10 am (0900 GMT) and was due to run until 8 am (0700 GMT) on Sunday.
Police said they had tightened security in Paris because of Internet and SMS text messages calling for riots in the centre of the capital, which has largely escaped the violence.
Three thousand extra police were brought into the capital on Friday, the Armistice Holiday marking the end of World War One, and there were no initial reports of any violence in the city.
Two shops were destroyed in Rambouillet, south-west of Paris, and a person on a scooter threw two fire bombs at a mosque and in the southern town of Carpentras before fleeing.
There was no major damage and no one was hurt but Chirac, Prime Minister Dominique de Villepin and the French Council of the Muslim Faith (CFSM) swiftly condemned the attack.
"We firmly ask the authorities in particular to protect our mosques, which seem to be becoming the target of violent demonstrations and provocation's," the CFSM said.
Police said it was not clear if it was a racist act or an act of provocation.
The unrest was triggered by the accidental deaths of two youths who were electrocuted as they hid in a power substation while apparently fleeing police just north of Paris.
Many of the youths in the suburbs complain of racism and harsh treatment by police. Eight policemen were suspended on Thursday after two of them beat a young man they had detained in Seine-Saint-Denis, north of Paris, and the other six looked on.
Police said the young man had been detained again overnight after an incident in which youth set a car on fire and threw stones at firemen.