French President Emmanuel Macron led a crisis meeting on Sunday after anti-government protests in Paris that left 263 people injured and widespread destruction around the capital.
Macron met with the prime minister, interior minister and top security service officials at the presidential palace in Paris after flying in from the G20 summit in Argentina.
Paris police said 412 people were arrested on Saturday during the worst clashes for years in the capital and 378 were still in custody.
A total of 133 had been injured, including 23 members of the security forces who battled rioters for most of the day in some of the most famous parts of the capital.
"I will never accept violence," Macron told a news conference in Buenos Aires before flying home.
"No cause justifies that authorities are attacked, that businesses are plundered, that passers-by or journalists are threatened or that the Arc du Triomphe is defiled," he said.
As protests took place across the country, a motorist died overnight after crashing a van into traffic which had built up due to a "yellow vest" demonstration in Arles, southern France, a local prosecutor said Sunday.
The so-called "yellow vest" anti-government protests that have swept France over the last fortnight were sparked initially by a rise in taxes on diesel.
In a separate incident, a motorway pay booth was set on fire by arsonists in southern France near the city of Narbonne, a judicial source told AFP Sunday. Five people were taken into custody, a prosecutor said.
The main north-south motorway in eastern France, the A6, was also blocked by protesters near the city of Lyon on Sunday morning, its operator said.
The capital was calm, however, but as groups of workers moved around cleaning up the mess from the previous day, the scale of the destruction became clear.
Around famous areas including the Champs-Elysees, the Louvre museum, the Opera and Place Vendome, smashed shop windows, broken glass and the occasional burned-out car were testament to the violence.
Dozens of cars were torched by the gangs of rioters, some of whom wore gas masks and ski goggles to lessen the effects of tear gas which was fired continually by police.
One person was in a critical condition after protesters pulled down one of the huge iron gates of the Tuileries garden facing the Louvre museum, crushing several people.
Nearly 190 fires were put out and six buildings were set alight, the interior ministry said.
At the Arc de Triomphe, a monument to France's war dead, graffiti had been daubed, with one slogan saying: "The yellow vests will win."
This was a reference to the so-called "yellow vest" anti-government protests that have swept France over the last fortnight, sparked initially by a rise in taxes on diesel.
The movement has since morphed into a broad opposition front to Macron, a 40-year-old pro-business centrist elected in May 2017.
Violent anarchist and far-right groups have since infiltrated it and are thought to be behind Saturday's clashes.
Macron faces a dilemma in how to respond to the "yellow vests", not least because they are a grassroots movement with no formal leaders and a wide range of demands.
Some representatives have also insisted on public talks broadcast on TV.
"We have said that we won't change course. Because the course is good," government spokesman Benjamin Griveaux told BFM television defiantly on Sunday morning.
"It's been thirty years that people change course every 18 months," he added, referring to Macron's presidential predecessors who have often caved in to pressure from French street protests.
Macron has so far refused to roll back taxes on fuel, which he says are needed to fund the country's transition to a low-emission economy.
And he remains a fervent defender of the tax cuts he has delivered for businesses and high-earners, which he believes were necessary to lower the country's chronic high unemployment.
"We're at a time when a bit of national unity around our security forces, around those who are really struggling would be a good thing for the country," Griveaux added.
State of emergency?
An estimated 75,000 demonstrators, most of them peaceful, were counted across the country on Saturday, the interior ministry said.
The number was well below the first day of protests on November 17, which attracted around 282,000 people, and also down from the 106,000 who turned out last Saturday.
Interior Minister Castaner attributed the violence to "specialists in sowing conflict, specialists in destruction".
He did not rule out imposing a state of emergency -- a demand made by the police union Alliance -- declaring: "Nothing is taboo for me. I am prepared to examine everything."
Two people have died and dozens have been injured in the rallies, which opinion polls suggest still attract the support of two out of three French people.