Macron pledged "to receive the planet in the best possible conditions of security organisation, social and ecological responsibility".

He also said that one of the major environmental targets of the Paris 2024 is now within reach after the investment of €1.4 million (£1.23 million/$1.5 million) to clean up the rivers Seine and Marne for open water events.

"At 500 days we are on track to achieve what will be one of the greatest legacies of the Paris 2024 Olympic and Paralympic Games, this will be a little revolution for the inhabitants," he said.

Meanwhile, on the banks of the Seine, Sports and Olympic and Paralympic Minister Amelia Oudéa-Castéra set in motion the French leg of a 24-hour relay to celebrate the milestone.

"We are hard at work, with still a lot of things to do and with a fierce determination to deliver the best possible organisation, a beautiful popular celebration and work on a lasting and ethical legacy," Oudéa-Castéra told radio station France Inter.

The relay has been organised as part of the Paris 2024 Terre de Jeux programme, with the assistance of French embassies and authorities in French overseas territories.

Each activity had been timed to begin at 9AM local time.

The 24 hour-relay began in New Zealand, where French Ambassador Laurence Beau made an early morning run along the waterfront in Wellington.

In Fiji, a race for schools was organised by French embassy staff.

"We pay tribute to each country's sports and athletes, their talent and their performance," French Ambassador François-Xavier Leger said.

"We also spread the Olympic and Paralympic values and we contribute to get more people moving, to unite the sports movement around our respective organisations, workforce and more importantly our communities."

In Australia, children were invited to take part in a swimming relay at the Telopea Park School in Canberra before the relay passed over to 2032 host city Brisbane, where the Baton was taken on by children at the Whiteshill State College.

As it continued its global journey, temperatures proved considerably lower in Helsinki with snow on the ground as participants carried the Baton past the Olympic stadium and statue of the great Finnish runner Paavo Nurmi.

In 1924, when the Games were last held in Paris, Nurmi won five gold medals in athletics.

Organisers have claimed that by the time the relay is complete, some 20,000 will have taken part in 116 countries.