Around 300,000 people took part in protests in Paris on Tuesday according to the CGT union, the lowest turnout since protests against the government's unpopular pension reform started at the beginning of the year.
The police, however, estimated that only 31,000 turned out in Paris.
In total, more than 900,000 people demonstrated across the country according to the CGT. The Interior ministry said the figure was closer to 280,000.
Several dozen CGT trade union militants briefly occupied the Olympics building in Aubervilliers, northern Paris, as around 250 marches got under way in towns and cities across France.
🔴 Le siège des JO 2024 à #Paris est envahis par la CGT pour protester contre la réforme des retraites. #manif6juin
— Clément Lanot (@ClementLanot) June 6, 2023
« Pas de retrait, pas de JO » pic.twitter.com/mm7L7hBJpP
Clashes were reported in the southeastern city of Lyon, a flashpoint in previous demonstrations, where projectiles were thrown at security forces, local authorities said.
Police, meanwhile, used tear gas in clashes with protesters in the western city of Nantes.
As part of Tuesday’s actions, a third of flights were canceled at Paris’ Orly Airport because of strikes, and about 10 percent of trains around France were disrupted.
'Last protest of this kind'
"This will be the last protest of this kind over the pension matter," Lauren Berger, head of the reform-minded CFDT trade union, said ahead of the protest in Paris.
Berger, who will step down on 21 June and will be replaced by Marylise Léon, added that the CFDT's aim was now to turn anger into a "show of strength" in talks with the government on issues such as improving work conditions and purchasing power.
"It's going to be another big day in the history of the trade union movement," the new head of the hard-left CGT union, Sophie Binet, told BFM television on Tuesday. "After six months the unions are still united and the level of anger, frustration and motivation is high."
"I hear people say sometimes that everything is over, but it's not true."
The head of the hard-left France Unbowed (LFI) party Jean-Luc Melenchon insisted the "struggle will continue" while admitting it was not clear "under what form".
Trade unions have fought President Emmanuel Macron's move to make the French work longer since mid-January, with rolling strikes and protests that have at times descended into violence on the fringes.
Macron’s move to raise the retirement age from 62 to 64 - and force the measure through parliament without a vote - inflamed public emotions and triggered some of France’s biggest demonstrations in years.
Parts of the pensions overhaul, including the key increase in the retirement age, were printed Sunday in France's official journal, meaning they are now law.
Opponents are pinning their hopes on a motion put forward by the small Liot faction in parliament - broadly backed by the left - to repeal the law and reverse the increased retirement age.
Parliament speaker Yael Braun-Pivet, a member of Macron's party but officially neutral, was to rule on Thursday whether a vote could go ahead.
Most observers expect her to declare the bid to be unconstitutional.
Having faced down the biggest protests in a generation to push through the changes, Macron appears intent on moving on, having concluded that voters now view the changes as inevitable and support for the demonstrations is waning.
The president Tuesday refused to comment on the issue as he attended commemorations for the 79th anniversary of D-Day, saying that "this is a moment to celebrate the unity of the nation".
Some protesters have already threatened to disrupt next summer's Olympics if Macron does not back down.
Banners reading "No retirement, No Olympics" were visible in Paris.
(with newswires)