Youths in Paris suburbs and the southern city of Toulouse torched several cars and set rubbish bins ablaze in the third night of violence. But officials reported no major clashes between youths and police, who were out in force.
Shortly after returning to France after a trip to China, Mr Sarkozy went to a hospital in the northern Paris suburb where a senior police officer is being treated for serious injuries after he was attacked at the start of the violence on Sunday.
Mr Sarkozy, a law-and-order hardliner when interior minister during riots two years ago, vowed to bring to justice rioters who had shot at police.
"Those who take it upon themselves to shoot at police will find themselves in the Assizes Court," Mr Sarkozy said. Shooting at police "has a name - attempted murder," he added.
"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."
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. It spread on Tuesday night to the southern city of Toulouse, where a library was attacked and about 20 cars were set ablaze. © 2007 Australian Broadcasting Corporation