After a century-long wait, Paris welcomed back the Olympic Games with a rainy yet historic ceremony held on the River Seine.

French President Emmanuel Macron declared the Games open before the waterborne ceremony reached its climax when Teddy Riner and Marie-Jose Perec lit the cauldron with the Olympic flame.

Han Zheng, Chinese vice president and President Xi Jinping's Special Representative, was among a host of international dignitaries in attendance at the opening ceremony.

International Olympic Committee President Thomas Bach expressed his gratitude towards the organizers and the French people.

"You are bringing our Olympic Agenda reforms to life by making these Games wide open. All of us will experience Olympic Games that are more inclusive, more urban, younger and more sustainable - the first Olympic Games with full gender parity on the field of play," said Bach.

For the first time in Olympics history, the opening ceremony took place outside the host city's main Olympic stadium. From the Austerlitz Bridge to the Trocadero, around 6,800 athletes, assembled behind their flagbearers, cruised down a 6km stretch of the Seine on 85 boats.

Despite the rainy conditions, the parade allowed athletes to bask in the beauty of Paris' most famed monuments, including the Louvre, Place de la Concorde, the Grand Palais and the Eiffel Tower, with some playing host to the opening ceremony's musical performances.

The 2024 Olympics marks the third time that Paris has hosted the Summer Games. The first was in 1900, and the last was a century ago in 1924.

Hours before the opening ceremony, arson attacks on French railways caused widespread delays and cancellations to rail services across Europe, casting a shadow over the sporting extravaganza.

The attacks, however, did not dampen the mood surrounding the ceremony, as crowds crammed the Seine's banks and bridges to watch.

China has dispatched a delegation of 405 athletes, including 42 Olympic champions, who will compete in 236 events across 30 sports at the Games.