French President Nicolas Sarkozy pledged on Wednesday to punish rioters who shot at police but sought to ease tensions with an independent probe into the deaths of two youths that triggered the unrest.
Youths in Paris suburbs and southwestern Toulouse torched several cars and rubbish bins in the third night of tension, but a heavy police clampdown in the Paris area saw a sharp drop in violence from the two previous nights.
Officials reported no major clashes between youths and police.
Moments after arriving back in France from China, Sarkozy sped off to a hospital in the Eaubonne suburb of Paris where a senior police officer, attacked at the start of the violence on Sunday, was being treated for serious injuries.
Sarkozy, a law-and-order hardliner when interior minister during riots two years ago, praised the officer's courage and said nothing could justify such violence.
Those who take it upon themselves to shoot at police will find themselves in the Assizes Court which handles serious cases, he told reporters later.
Shooting at police has a name -- attempted murder.
We will find the shooters. We will put in the necessary resources ... It is not something that we can tolerate, no matter how dramatic the deaths of these two youngsters on a motorbike may be, he added.
The violence has revived memories of the riots in 2005, the worst unrest in France in 40 years, when thousands of cars were torched after two teenagers were electrocuted in a power sub-station after apparently fleeing police.
The new wave of violence erupted on Sunday when two teenagers were killed in a collision with a police car.
But an official in the riot-affected areas said the level of violence overnight had halved from Monday, when about 80 police officers were injured in clashes with youths.
Prime Minister Francois Fillon told parliament a heavy police presence on Tuesday night had helped restore calm: Last night there were 1,000 police on the ground ... and we saw the results -- there was a very noticeable drop in violence.
Officials have said the latest unrest was nowhere near the scale of 2005 and was limited to a few areas, though the use of firearms so early in the disturbances has alarmed police.
During a flurry of meetings apparently designed to show he was ready to tackle pressing domestic problems after his China trip, Sarkozy met the crash victims' parents. He agreed a formal manslaughter probe by an independent investigating judge would be opened, a key demand of the families.
It's a gesture that is just, and aims to calm the situation which we would like, in the name of all the families, to be heard everywhere, their lawyer Jean-Pierre Mignard said.
A public prosecutor has said an initial crash report cleared police of blame in what she said was a road traffic accident. Questions remain, however, over police actions after the crash and the speed with which help arrived.
Tense relations with police, high unemployment, poor schools, inadequate housing and tougher immigration laws have created a generation of frustrated youths in rundown areas.
The government said it planned to unveil a plan to boost jobs in tough suburbs on January 22, but warned it would not repeat past mistakes by throwing billions of euros at the problem.
(Reporting by Laure Bretton and Sophie Louet; Writing by Jon Boyle; Editing by Charles Dick)