The French government has authorised a range of emergency powers an effort to end the country's worst civil unrest in decades. However, the measures have failed to prevent new unrest from breaking out tonight.
The protests, blamed on racism and unemployment, have continued for 12 nights and prompted President Jacques Chirac's government to declare a state of emergency today.
The move was announced by interior minister Nicolas Sarkozy, whose resignation rioters are seeking, and allows local authorities to impose curfews and lets police perform raids without warrants.
The government held a special meeting to adopt a decree under a 1955 law that allows regional government officials known as prefects to impose curfews in areas where they consider it necessary.
The decree was due to go into force at midnight. It allows emergency measures to be in force for 12 days and can restrict the movement of people and vehicles in areas where local government officials known as prefects declare a curfew.
But youths threw firebombs at police and set fire to vehicles near the southwestern city of Toulouse this evening, and isolated acts of violence broke out in other parts of France.
The northern city of Amiens was the first to announce a curfew, saying unaccompanied youths would not be allowed to walk the streets of the city and neighboring districts from midnight until 6.00am. In coming days the curfew will start at 10.00pm. Police, meanwhile, said unrest last night was still widespread and destructive but not as violent as previous nights.
"The intensity of this violence is on the way down," National Police Chief Michel Gaudin said, citing fewer attacks on public buildings and fewer direct clashes between youths and police. He said rioting was reported in 226 towns across France, compared with nearly 300 the night before.
Nationwide, vandals burned 1,173 cars overnight, compared with 1,408 vehicles on Sunday night, police said. A total of 330 people were arrested, down from 395 the night before.
A police spokesman said 76 vehicles had been set ablaze and 57 people detained in violent incidents across France so far tonight, but there had been no major clashes. "At the moment, the beginning of this night is a bit calmer than the beginning of last night," the spokesman said.
More than 5,000 cars have now been set on fire during the 12 days of unrest and more than 1,500 people have been detained, some of them white youths but most of them of Arab and African origin.
The recourse to a 1955 state-of-emergency law that dates back to France's war in Algeria was a measure both of the gravity of mayhem that has spread to hundreds of French towns and cities and of the determination of Chirac's sorely tested government to quash it.
Prime Minister Dominique de Villepin said curfew violators could be sentenced to up to two months imprisonment, adding that restoring order "will take time." He said 1,500 police would be brought in to back up the 8,000 officers already deployed in areas hit by violence.
"Some parts of towns could thus see themselves faced with the application of measures banning or restricting the movement of people and vehicles," he said.
"Refusal to abide by them could pave the way for criminal sanctions that could be up to two months in prison."
Mr de Villepin also acknowledged racial discrimination in France that has inflamed tempers in the heavily immigrant suburbs. He said job-seekers with foreign-sounding names are sometimes not given equal consideration as those with traditional French-sounding names when they present their CVs.
Fears over the violence helped push down the value of the euro, and French officials are worried the country's worst unrest in decades could hit investment and tourism.