Alain Robert, the free climber dubbed the "French Spider-Man", on Monday scaled the Tour Total, a 48-storey skyscraper in Paris, to demonstrate support for workers striking against President Emmanuel Macron's pension reform plans.
Robert, 57, stood with both arms aloft after reaching the summit of the 187-metre (613-foot) high tower, which stands in the French capital's business district, La Defense.
"I am trying to use my fame for something I find meaningful," Robert told Reuters, adding that he was himself "deeply concerned" by the pension reform plans.
"Sponsors only give me money if I climb," he said.
France has been dogged by strikes and street protests for more than a month as unions push back against Macron's drive to streamline the pension system and avert a looming 17 billion euro pension deficit.
Macron's government said on Saturday it was willing to withdraw a proposal to raise the retirement age to break the deadlock with unions.
Robert has climbed more than 100 structures, including the Golden Gate Bridge in San Francisco and the world's tallest building, the Burj al Khalifa in Dubai.
Monday's ascent was the ninth time that Robert had climbed the Total tower.
Robert often climbs without permission and has been arrested on numerous occasions. He climbs without a harness, using only his bare hands, a pair of climbing shoes, and a bag of powdered chalk to wipe off the sweat.