More than 2000 people were arrested and at least 600 police officers were injured in France after fringe groups targeted public buildings, looted luxury boutiques and supermarkets, and attacked police vehicles and officers.
Flames engulfed the 19th-century City Hall in the city of Limoges, in central France, causing its roof to collapse and nearly destroying the building.
In Marseille, black-clad protesters broke into city hall and defaced the building with anarchic graffiti. And in Lyon, protesters torched the city's tourist office.
Tensions erupted in Paris, where protesters were blocked from marching on government buildings and police used tear gas as they retreated from mostly young protesters, many of whom wore hoodies, masks and goggles.
"I am actually stunned by the level of destruction and violence that was expressed," government employee Marie Peyreigne, 57, said.
President Emmanuel Macron echoed other government officials in blaming much of the violence on far-left activists, accusing them of attacking police and public buildings to foment chaos, saying they had been "joined by numerous criminals".
"Those who looted will have to pay for the damage, and those who sought to bring down the Republic will be held accountable," Macron said in a televised address to the nation.
Macron earlier held an emergency meeting with senior government officials, and said he had instructed prefects to work with mayors to protect public buildings and businesses in coming weeks - including by banning protests when necessary.
Macron declined Interior Minister Laurent Nunez's offer to resign, saying he should stay to ensure a chain of command is retained within the police and security forces.
Prime Minister Sebastien Lecornu said the government would not be "intimidated" by "those who clearly want to use this violence as a 'warm-up' before the presidential election".
"No one will impose their political agenda through violence," he wrote on X.
Authorities estimated marches in France on Saturday had a turnout of about 550,000, while organisers put it at 800,000.
Smaller-scale protests also unfolded in Belgium, Portugal and Italy as living costs rise in Europe, while protesters in Albania again rallied against perceived government corruption, a lack of jobs and poor education standards.
Protesters said most people had marched peacefully and blamed much of the chaos on troublemakers who had set out to cause damage and clash with police.
In Italy, masked youths went on a violent rampage in the northern city of Milan for a second consecutive day, smashing shop windows and looting, prompting police to use tear gas and water cannons.
Officers detained at least 160 people, around 80 per cent of them minors.
Police also used water cannons to try to disperse crowds in Bologna.
In Brussels, protesters rallied against rising education costs and reforms they fear will make higher education less accessible.
In Portugal, unrest stemmed from housing and other living costs.
Residential property prices in Portugal have doubled since 2017, fuelling one of Europe's worst affordability crises.
In Albania, police fired what appeared to be rubber bullets at protesters during a fifth day of mass student demonstrations calling for Prime Minister Edi Rama to step down.
The protests in France began in September at high schools in Paris' working-class northern suburbs, where anger over teacher shortages and shabby facilities evolved into a broader movement focused on inequality, public spending and living standards.
Protests against housing costs and forced evictions have also unfolded in Spain since late September.
Over the chaotic weekend in France, a 17-year-old girl was injured at a demonstration and lost an eye, and a young protester lost a hand, heightening scrutiny of police use of grenades and other riot-control weapons.
With AP and DPA
25°C