Riot police clashed with protesters on Friday evening in Paris as a new demonstration took place against the government's plans to raise the French state pension age.
Protesters were on the streets for most of Friday as President Emmanuel Macron was warned he was “playing with fire” by forcing through his pension reform without a vote.
Mr Macron's government is bracing for a no-confidence motion after using special powers to pass the bill without support from MPs.
As furious opponents accused Mr Macron of a “denial of democracy”, trade unions vowed to continue their struggle against the change to the retirement age.
Protesters lit flares on a Paris ring road early on Friday after cars and bicycles were burnt and effigies of Mr Macron set alight in a wave of unrest.
About 300 people were arrested in the latest skirmishes.
Unrest has grown since the start of the year, with a series of strikes hitting the country, including one by bin collectors, with rubbish piling up on the streets of Paris.
Unions called for new protests at the weekend and another day of mass strikes and mobilisation next Thursday.
Senator Esther Benbassa said the streets had “taken the floor” after a National Assembly vote was cancelled.
“When you trample on parliament, ignore a massive and peaceful mobilisation, scorn a united front from unions and violate democratic principles, what do you get?” she said.
“By playing with fire like this, you risk a blaze.”
Mr Macron's supporters said the government had acted responsibly and that MPs would have the final say in a confidence vote.
Although the French Senate backed the pension bill by 193 votes to 114, a division in the National Assembly was cancelled, with Mr Macron's camp unable to secure a majority.
Left-wing MPs heckled and sang the national anthem after Prime Minister Elisabeth Borne announced she was invoking Article 49.3 of the constitution to force the bill through.
The bill raises the retirement age from 62 to 64, a move intended to cut the costs of the welfare state, but is bitterly opposed on the left and parts of the right.
France's biggest unions said in a joint statement that the government was responsible for the “social and political crisis” resulting from the bill.
“The unions continue to demand the withdrawal of this reform,” they said.
Thursday's move was an acknowledgement that centre-right Republican MPs had failed to back Mr Macron's party in sufficient numbers despite their leader, Eric Ciotti, supporting the bill.
“We wanted to vote for the compromise text agreed between MPs and senators, notably including the Republicans. Unfortunately, too many Republican MPs preferred to play their own cards,” said pro-Macron Senator Charles Rodwell.
The Article 49.3 gambit means the bill becomes law unless MPs swiftly pass a no-confidence motion.
Left-wing leader Jean-Luc Melenchon and far-right presidential hopeful Marine Le Pen both said they would support such a vote.
Mr Macron's government may survive with centre-right backing after Mr Ciotti said he would oppose the no-confidence motion, but all eyes will be on rebels in the Republican ranks.
Defeat for Mr Macron would force him to appoint a new government or call new elections.