At Paris' main airport, Roissy-Charles De Gaulle, workers blocked access to a terminal, forcing some travellers to get there on foot. Flight services will continue to be reduced at the weekend, France's civil aviation authority said.

The president broke weeks of silence on the new policy to say he would stand firm and the law would come into force by the end of the year, at one point comparing the protests to the storming of the U.S. Capitol in January 2021. Laurent Berger, the head of France's biggest union, the moderate CFDT, told BFM TV that Macron's comments "increased the anger."

The past seven nights have seen demonstrations in Paris and other cities, with rubbish bins set ablaze and scuffle with police. The latest wave of protests represents the most serious challenge to the president's authority since the "Yellow Vest" revolt four years ago.

Near Toulouse, in the southwest, plumes of smoke were seen rising from burning piles of debris blocking traffic on a highway. Protests also targeted oil depots and blocked an LNG terminal in the northern city of Dunkirk. Electricity output was cut as unions raised pressure on the government to withdraw the law.

Since January, rallies organized by unions have drawn huge crowds in protests against the new law, which also accelerates a planned increase in the number of years one must work to draw a full pension. While most protests have been peaceful, anger has mounted since the government bypassed a vote in the lower house of parliament.

"It's a good thing that people are still mobilizing and that people stand up for their beliefs," said 26-year-old engineer Jean Walter at the Paris Saint-Lazare train station, where many trains were cancelled. "I'm supporting the strike, even if it will take more time to go to work today."

Protesters, wearing French CGT labour union vests, attended demonstrations in Nantes. The slogan showing the drawing of a skeleton reads "long live retirement". Unions also blocked the train tracks at Paris’ Gare de Lyon station, BFM TV footage showed.

Across the country, small groups of protesters engaged in wildcat actions, burning debris to block traffic and gathering with banners reading "No to the pension reform."

Students also attended the demonstration in Nantes, France.

Macron said on Wednesday that he had tasked his prime minister, Elisabeth Borne, with finding more support for the government. He said he wanted to involve unions more in upcoming policy changes on issues including schools, health or the environment. Labor Minister Olivier Dussopt said the government was not in denial about the tensions but wanted to move on.