Police in the French city of Lyon have used teargas to disperse youths throwing stones and attacking cars.
The Lyon unrest was the first in a major city centre
Two people were arrested on the city's famous Place Bellecour square, in the first rioting in a major city centre.
The unrest, which followed more than two weeks of violence in France's poor suburbs, occurred hours before a curfew for minors came into force in Lyon.
In Paris, thousands of police are enforcing a ban on public meetings and the situation has remained calm.
The ban will remain in force until Sunday morning.
Police overnight said the situation across France was "much calmer" than on previous nights.
However, cars were set alight in the southern city of Toulouse and near St Etienne in the south-east.
A nursery school was torched in the southern town of Carpentras.
The trouble in Lyon began at about 1700 (1600 GMT) on Saturday on Place Bellecour, where a large number of riot police were on duty as a preventative measure.
About 50 youths attacked stalls and damaged vehicles, witnesses told Reuters news agency.
Shoppers hurried away from the area and most shopkeepers closed their doors.
Officials in Lyon and 10 towns to the east of the city earlier announced a curfew to bar unaccompanied minors from the streets over the weekend between 2200 (2100 GMT) and 0600 (0500 GMT).
Interior Minister Nicolas Sarkozy blamed the Lyon violence on a "demonstration by anarchists" without elaborating.
The government has declared a state of emergency in Paris and more than 30 other areas to help quell the unrest.
The Paris ban on meetings, imposed under new emergency measures, prohibits "all meetings likely to start or fuel disorder".
It was announced after police reports of e-mails and text messages calling for "violent acts" in the city.
Security was tight at the Stade de France stadium, in the riot-hit northern suburbs of Paris, for a football match between France and Germany.
Provides for state of emergency, regional curfews, house searches, house arrest
Public meeting places can be closed down and media, film and theatre showings may be controlled
Breach of curfew could mean two-month jail sentence
Mr Sarkozy has been inspecting police units in the capital, which have been beefed up by at least 2,000 extra officers from outside Paris.
The BBC's Nick Thorpe in Paris says there has been no sign of trouble there.
Either the messages were sheer bravado or the publicity given to them by police has scared potential participants away, our correspondent says.
Several hundred people rallied close to police headquarters in central Paris on Saturday to protest against alleged discrimination against youths of immigrant origin.
The country's unrest was triggered by the deaths in the run-down Paris suburb of Clichy-sous-Bois of two youths, who were accidentally electrocuted at an electricity sub-station.
Locals said they were fleeing police but the police deny this.