Angry protests have erupted in Paris and other French cities after President Emmanuel Macron's government on Thursday rammed a controversial pension reform through parliament without a vote.
The premier used a special constitutional power enabling the government to pass legislation without a vote, which was an admission that the government lacked a majority to raise the retirement age from 62 to 64.
After the Senate adopted the bill earlier on Thursday, right-wing opposition MPs in the National Assembly were reluctant to side with Mr Macron, meaning the government faced defeat in the lower house.
"We can't take the risk of seeing 175 hours of parliamentary debate come to nothing," Prime Minister Elisabeth Borne told MPs.
Ms Borne announced the government's move amid jeers and boos from opposition MPs, who also sang the national anthem.
A crowd of thousands gathered in front of the parliament in the historic Place de la Concorde in central Paris, watched by riot police.
"I'm outraged by what's happening. I feel like I'm being cheated as a citizen," said schoolteacher Laure Cartelier, 55.
"In a democracy, it should have happened through a vote."
At about 8pm, police used tear gas and water cannon to clear protesters away after a fire was lit in the centre of the square, close to an Egyptian obelisk that has stood there for almost 200 years.
About 120 people were arrested on suspicion of seeking to cause damage, Paris police said.
Even after the rally was dispersed, some protesters started fires and caused damage to shopfronts in side streets, AFP reported.
Several shops were looted during protests in the southern city of Marseille, while clashes between protesters and security troops erupted in the western cities of Nantes and Rennes, and Lyon in the south-east.
Trade unions and political analysts had warned that adopting the legislation without a vote, by invoking Article 49.3 of the Constitution, could enrage opponents and would undercut the law's democratic legitimacy.
"It's a total failure for the government," far-right leader Marine Le Pen said. "From the beginning the government fooled itself into thinking it had a majority."
Polls showed two thirds of French people oppose the pension overhaul.
"When a president has no majority in the country, no majority in the National Assembly, he must withdraw his bill," said Socialist Party chief Olivier Faure.
Some opposition parties including that of Ms Le Pen are set to call a no-confidence vote in the centrist government on Friday.
But Ms Borne's Cabinet is expected to survive, thanks to backing from the right-wing Republicans party.
Unions immediately scheduled another day of mass strikes and protests for next Thursday, calling the government's move "a complete denial of democracy".
Antoine Bristielle, a public opinion expert at the Jean Jaures Foundation think tank, told AFP that enacting such an important law without a vote could further antagonise the country and deepen anti-Macron sentiment.
Opinion polls showed that about eight out of 10 people opposed legislating in this way, while a growing number of people were losing faith in French democracy, Mr Bristielle said.
After trying and failing to push through a pension reform during his first term, Mr Macron returned to the issue while campaigning for re-election last April.
But he lost his parliamentary majority in June after elections for the National Assembly.
Despite the day of high drama, Mr Macron made no public comment on the matter on Thursday.
"You cannot play with the future of the country," he told a closed-door Cabinet meeting, a participant said.
Trains, schools, public services and ports have been affected by strikes since January amid some of the biggest protests in decades.
A rolling strike by municipal waste collectors in Paris has led to about 7,000 tonnes of uncollected trash piling up in the streets, attracting rats and dismaying tourists.
Images showed that protesters in Paris and other cities took advantage of the situation to set fire to the uncollected rubbish.
The political implications of forcing through a reform opposed by most of the population are uncertain.
The head of the CGT union, Philippe Martinez, warned this week that Mr Macron could be "giving the keys" of the presidency to Ms Le Pen at the next election in 2027.
Mr Macron will not be allowed to seek a third term in that election under the French Constitution.
