More than 100 police officers were injured after an outbreak of violence at pension protests in France, the interior ministry has said.
Interior minister Gerald Darmanin said the number of wounded officers was extremely rare, and added 291 people had been arrested during the unrest.
Officers clashed with hundreds of black-clad demonstrators in Paris and other cities during union-led May Day protests against President Emmanuel Macron’s increase in the retirement age.
Demonstrators pelted Paris police with Molotov cocktails and fireworks, torched building materials and smashed up bus stops.
Protesters marching peacefully booed the police as they responded with tear gas and baton charges.
Emergency services used water cannons to put out a fire which burned the windows of nearby flats. One officer was badly injured when he was hit by a fiery projectile.
Unrest also erupted in Lyon, where several vehicles were set ablaze and some business premises were trashed.
Meanwhile, in Nantes in western France, a fire broke out in front of a local administration building during the protests.
Emmanuel Macron’s popularity has plunged to near record lows after he defied unions to lift the retirement age by two years to 64.
Sophie Binet, leader of the left-wing CGT union, said the pension reform had left Mr Macron isolated.
“The executive cannot govern without the support of its people," Ms Binet said ahead of the Paris protest, adding her union had not yet decided on talks with the government on other matters in the weeks ahead.
Laurent Berger, head of the more moderate CFDT trade union, said Mr Macron’s government had been deaf to the demands of one of the most powerful social movements in decades.
He said his union was open to discussions with the government and dismissed suggestions that a rare alliance between the leading trade unions was being tested now that the pension bill had been signed into law.
“We must bring other proposals over salaries and working conditions to the table," he told BFM TV.
Mr Macron says the French reform is needed to keep one of the industrialised world’s most generous pension systems in the black.
French pension payments as a share of pre-retirement earnings are comfortably higher than elsewhere and a French man typically spends longer in retirement than those in other OECD nations.
But trade unions say the money can be found elsewhere.
Elsewhere in Europe, union-led protests are planned throughout Germany, while in Italy, the three main unions held a rally in the southern city of Potenza.
In Switzerland, a parade through Zurich took place without major incident, Zurich police said.