Violence broke out in France on Saturday as left-wing demonstrators trampled on Israeli and American flags and threw firebombs at police.
In Paris, clashes began as the march reached its planned endpoint, with officers confronting protesters in the streets.
Some demonstrators used hammers to loosen paving stones before throwing them at police. At least one incendiary device was also launched toward security forces, who replied with tear gas.
Thousands of young people gathered across France, Germany, Italy and Spain as authorities prepared for a potentially violent third weekend of demonstrations.
France deployed around 70,000 police officers and gendarmes, while the Paris march was redirected toward the edge of the capital.
Youth-led rallies were also reported in Germany and Italy.
French Interior Minister Laurent Nuñez warned that there was a “very high risk” of disorder, particularly after nightfall on Halloween.
Thousands of people had already been arrested after riots and looting disrupted protest marches that were otherwise largely peaceful on October 17 and October 24.
Demonstrators march through Paris during a protest over the rising cost of living on October 31
A demonstrator waves a French flag through clouds of tear gas during a nationwide rally in Lyon
French police patrol before Saturday’s demonstration, with officials warning of possible disorder
At Porte de Bagnolet on Paris’s eastern outskirts, several thousand people began assembling on Saturday afternoon behind a group of students who were due to lead the march hand in hand.
CGT union security members guarded the front of the crowd, while police units gathered in nearby side streets.
The protesters were united by a range of complaints rather than a single cause.
Separate groups carried their own signs, including high school students opposing the university admissions system, climate campaigners and demonstrators protesting the rising cost of living.
Halloween costumes added a theatrical element to the crowd, with a Thriller-era zombie Michael Jackson, a pirate and Spider-Man among those spotted.
For much of the afternoon, protesters waited peacefully, singing and chanting through megaphones.
Corentin Cabreux, a 21-year-old student, said his state-run accommodation had “damp stains all along the bottom of my walls, whole sections peeling off, cockroaches everywhere, rats”.
He said he hoped the Halloween rally would have a festive atmosphere and challenge the image of violence that has increasingly become associated with France’s protests.
Police impose curfews and restrictions in an effort to prevent further violence
The demonstrations began last month with high school students protesting deteriorating school buildings, teacher shortages and a university admissions process they believe disadvantages poorer pupils.
Trade unions and other groups opposed to President Emmanuel Macron soon joined the movement, bringing a wider set of demands.
Demonstrators carrying banners, flags and costumes join a Yellow Vest protest at Porte de Bagnolet
A protester in a Scream mask holds a placard featuring French President Emmanuel Macron
Although most participants have remained peaceful, groups of masked troublemakers have repeatedly attacked police with fireworks and other projectiles.
Several rallies have descended into rioting and looting, including the unrest on October 17 that appeared to catch the government off guard.
Police have used tear gas, dispersion grenades, water cannon and other measures, some of which have left protesters and officers seriously injured.
Mr Macron said the Saturday marches would be kept away from city centres in an effort to protect businesses.
Authorities also prohibited access to Place de la République and Les Halles between 11pm and 6am on Saturday and Sunday.
Unaccompanied minors were subject to a separate 9pm curfew around the Champs-Élysées.
However, a Paris court suspended an earlier order affecting minors on Wednesday, ruling that it represented a serious and unlawful restriction on freedom of movement.
Demonstrations were also scheduled in Germany, Italy and Spain.
In Germany, the youth movement “Gen Z regelt”, loosely translated as “Gen Z’s got this”, called for rallies in around 30 cities over education, healthcare, climate protection and affordable living, while opposing any revival of compulsory military service.
Organisers said more than 180,000 people had registered online.
MORE STORY: Towns Impose Halloween Curfews After Teen Mob Violence, Add Police
Berlin police anticipated a crowd of about 10,000 at the Brandenburg Gate. Several shops along the Kurfuerstendamm boulevard boarded up their windows, although officials said they had no information about a specific threat of violence.
The German protests were expected to begin early in the afternoon.
In Barcelona, Catalan police planned to activate their highest alert level after an anonymous TikTok network known as Blocus encouraged people to gather again.
Last Saturday’s unrest in the city resulted in roughly 130 arrests, most involving minors.
Police in Italy remained on alert following clashes in Milan, Turin and Bologna, while calls for demonstrations also circulated on TikTok in Belgium, the Netherlands, Austria, Switzerland and Portugal.
A protester displays a French flag during nationwide rallies over inequality and the cost-of-living crisis
A person wearing a Halloween mask stands as another demonstrator speaks into a megaphone in Paris
France banned Halloween masks at anti-government demonstrations nationwide as officials warned that the country could face another weekend of serious violence.
At least 4,000 people had been arrested during disturbances over the previous month, with hundreds more injured.
Interior Minister Laurent Nuñez said further rioting, looting and arson were a serious possibility on Saturday, which he described as a high-risk day involving 70,000 police officers and gendarmes.
He said face coverings would be prohibited despite the Halloween celebrations because authorities believed there was a “very high risk of public disorder”.
Mr Nuñez said police had identified several social media appeals urging people to attend Halloween gatherings and “spark a revolution”.
Some online messages encouraged participants to dress up and meet for “a night of darkness”.
Authorities prohibited demonstrations in the centres of several cities, including Paris, where the approved march was moved to the eastern section of the ring road.
Alain Di Crescenzo, president of France’s chamber of commerce, said businesses were “extremely worried”, with many retailers boarding up their premises.
French gendarmes stand in Paris ahead of Saturday’s expected demonstrations
Police vehicles stand near the Arc de Triomphe during nationwide protests linked to labour unions
Two security guards protect the entrance to a Dior store ahead of the demonstration
“Shopkeepers can’t wait for Saturday to be over,” Mr Di Crescenzo said.
“The information we have is that Halloween is not helping matters, because we are going to have people wearing masks.”
French authorities have admitted that intelligence failures contributed to earlier clashes and have sought to regain control through tighter protest restrictions and curfews.
The unrest grew out of weeks of high school protests calling for the equivalent of around £9 billion in additional education funding.
It has since expanded into a broad movement involving groups ranging from trade unions to Black Bloc anarchists.
Left-wing politicians have been accused of inflaming tensions, while those politicians argue that heavily armed police units have provoked demonstrators.
Jean-Luc Mélenchon, the presidential candidate for France Unbowed, said police had fired excessive amounts of tear gas at peaceful protesters.
“It seems that confrontation is the very goal of this public-order strategy. It’s pathetic,” he said.
Workers install protective barriers on a shop before Saturday’s expected protests
French authorities have acknowledged intelligence failures linked to earlier clashes
The boarded-up Dior storefront on the Champs-Élysées ahead of a Paris protest
The Yellow Vests, or Gilets Jaunes, were also present on Saturday. The movement brought widespread disruption to France during the early years of President Emmanuel Macron’s administration.
Opinion polls indicate that Marine Le Pen, the far-right National Rally candidate, could face Mr Mélenchon in the second round of France’s next presidential election in May.
Ms Le Pen is appealing a conviction for embezzling European Parliament funds. If the conviction stands, she could become the first convicted criminal to reach the Élysée Palace.
Mr Macron will be unable to seek another term after serving the maximum two terms permitted for a French president.