Fresh rioting broke out on the outskirts of Paris overnight as gangs of youths challenged authorities' vows to crack down on urban violence that has plagued the French capital for over a week.

Police said more than 160 cars were torched in the Paris region and 33 in the provinces, but the night seemed calmer than Thursday when 315 vehicles were burnt in the Ile-de-France region around the capital.

Buses, fire engines and police were again stoned in the Paris suburbs, with five policemen reported slightly injured by projectiles, but there were fewer direct confrontations between police and "troublemakers", according to a police spokesman.

One of the worst incidents took place at Neuilly-sur-Marne where police vans came under fire from pellet pistols, but nobody was hurt. Neuilly-sur-Marne is in the worst-hit northeastern region of Seine-Saint-Denis, where 1,300 officers were deployed, and more than 30 people were arrested there and elsewhere.

A fire was started in a primary school in Stains, as police were targeted by a group of 30 to 40 people near the synagogue.

Paris firemen were fighting a blaze at a carpet warehouse in Aulnay-sous-Bois in Seine-Saint-Denis. Dutch truckers told an AFP reporter that they had seen a group of youths briefly enter the building.

And for the first time since the troubles erupted on Thursday last week, there were sporadic signs of copycat rampages elsewhere in France.

Police said several cars in the eastern city of Dijon were set alight, while similar attacks took place in the western Seine-Maritime region and the Bouches-du-Rhone in the south of the country.

The rioting was a direct challenge to the authority of the French government and to Prime Minister Dominique de Villepin in particular.

Villepin on Thursday vowed before parliament that authorities "will not give in" to the violence and would make restoring order their "absolute top priority".

"I will not allow organised gangs to make the law in the suburbs," he declared.

The clashes have gained territory virtually every night since they began, exposing what sociologists and commentators said was a blatant failure of successive governments to address the problems of low-income, high-immigration suburbs dominated by grim public housing estates, some of them little more than ghettos where crime and gangs run rampant.