French high level climber Alain Robert climbs the Alto Tower, in La Defence near Paris, on Wednesday. AFP

Alain Robert, 60, climbs without a harness, using only his bare hands and a pair of climbing shoes.

"I'm here to show my support for those who oppose the pension reform," he told Reuters before starting his ascent of the 150-metre (492 foot) skyscrapper in Paris' La Defence business district.

Alain Robert climbs the Tour Alto skyscraper at the financial district of La Defense. Reuters

"I'm here to tell (President) Emmanuel Macron to come back down to earth ... by climbing with no safety net."

Robert said the pension reform, which Macron signed into law at the weekend after months of street protests, meant that, combined with a loss of income due to the COVID pandemic, he would have to keep on working, and climbing, for longer.

Alain Robert poses before climbing the Alto Tower. AFP

Under the reform, the French retirement age will gradually rise to 64 from 62. Robert has scaled more than 150 towering structures worldwide, including Dubai's Burj Khalifa — the world's tallest building —the Eiffel Tower, and San Francisco's Golden Gate Bridge.

Reuters