Youths in Paris suburbs and the city of Toulouse torched cars and set rubbish ablaze in fresh urban violence in France on Tuesday.
With police out in force, the situation remained tense.
But there were only isolated incidents of vandalism and officials reported no major clashes between youths and police in contrast to Monday night when around 80 police officers were injured when rioters pelted them with stones and petrol bombs.
"(The situation) is much calmer than in previous nights but you can feel all this remains fragile," Prime Minister Francois Fillon said after meeting officials in the northern Paris suburb of Villiers-le-Bel, where unrest erupted on Sunday.
The government pledged to take a firm line against rioters who attacked police, and there was a heavy police presence in Paris suburbs. Officers in riot gear and dozens of police vans lined the main street of Villiers-le-Bel, as a helicopter circled above.
Around a dozen cars were set ablaze in suburbs in Paris.
In Toulouse in the south vandals torched about 20 cars, police said. They also tried to set fire to a library in a working class district of the city, but police said they stepped in before there was any real damage.
The urban unrest, triggered by the deaths of two youths who were on a moped that collided with a police car, have posed a fresh challenge to the leadership of President Nicolas Sarkozy after transport strikes and student protests over his reforms.
The disturbances eclipsed his success in clinching billions of euros of contracts for French firms on a trip to China.
He was to meet Fillon and his interior and justice ministers to discuss the crisis on his return from China on Wednesday, his spokesman said. He would first visit injured police officers in hospital.
One police officer was hit by a projectile apparently fired from a hunting rifle in Monday's violence in which police replied with tear gas and rubber bullets, and made five arrests.
Fillon told parliament the clashes were "unacceptable, intolerable, incomprehensible" and could not be justified.
"Those who fire on the police and who beat a police officer nearly to death are criminals and must be treated like criminals," said Fillon, who visited Villiers in the evening.
The violence has revived images of 2005 riots when youths torched thousands of cars after two teenagers were electrocuted in a power sub-station after apparently fleeing police.
Many youths in the poor, ethnically diverse suburbs, where unemployment runs up to 40 percent, say they feel discriminated against by police and marginalised by mainstream society.
The 2005 disturbances were the worst civil unrest in France for 40 years and many blamed the harsh rhetoric of Sarkozy, interior minister at the time, for stoking the violence.
This time, Sarkozy has called for calm and the lower-key response of the government suggested it wanted to avoid exacerbating tensions in France's deprived suburbs.
Six Socialist mayors in northern Paris suburbs affected by the troubles renewed appeals for calm and urged parents to help them avoid more unrest.
"I ask the families, parents, to keep their children and teenagers at home tonight," Jean-Pierre Blazy, whose Gonesse district was hit by trouble overnight, told reporters.
During his China trip, Sarkozy urged calm after the initial unrest, comments criticised by Villiers resident Samir Ghrabi.
"Before preaching to others in China, Sarkozy should bring back human rights here. Here there is a justice for the poor, one for the rich and another for the police," he said.
Interior Minister Michele Alliot-Marie said criminals were using youngsters to distract police while they pillaged shops and denied a repeat of the 2005 riots was due, saying that in contrast to two years ago, the unrest was limited geographically. ( Reuters )