"So that things are very clear: What has happened is absolutely unacceptable," Sarkozy, said after meeting with a wounded police captain hospitalized in Eaubonne north of Paris .
It was the first time Sarkozy, who had just returned from China, had entered the fray of the renewed tensions in France's suburbs since the rioting broke out Sunday night.
The violence drew comparisons with riots that raged through suburbs nationwide in 2005, and shows that that anger still smolders in poor housing projects where many Arabs, blacks and other minorities live largely isolated from the rest of society. The renewed outburst was shaping up to be a stern test for Sarkozy.
"We will find the shooters," he said, and they will "be brought to account before justice."
He described the incident that sparked the violence - the death of two teens on a motorbike Sunday in an accident with a police car in the Paris suburb of Villiers-le-Bel - as "distressing." But he added: "Shooting at police has no link to this incident."
Sarkozy was meeting Wednesday morning with the families of the two teens, and with the mayor of Villiers-le-Bel before having a security meeting with his top ministers.
While cars were set ablaze for a third night Tuesday, officials said the violence was less intense than the two previous nights. Interior Minister Michele Alliot-Marie said the overall situation was "calm." Still, she said on Europe-1 radio, police presence would remain reinforced "as long as necessary."
She said 39 people were arrested in the Paris region Tuesday night.
Bands of young people set more cars on fire Tuesday in and around Villiers-le-Bel. In the southern city of Toulouse , 20 cars were set ablaze, and fires at two libraries were quickly brought under control, police said.
The previous night, 82 officers were injured, 10 of them by buckshot and pellets, the police force said. The use of firearms - rare in 2005 - added a dangerous dimension.
There have long been tensions between France's largely white police force and ethnic minorities trapped in poor neighborhoods. Despite decades of problems and heavy state investments to improve housing and create jobs, the depressed projects that ring Paris are a world apart from the tourist attractions of the French capital. Police speak of no-go zones where they and firefighters fear to patrol.
The violence two years ago also started in the suburbs of northern Paris , when two teens were electrocuted in a power substation while hiding from police.