Marie-Jose Perec and Teddy Riner light Olympic cauldron

PARIS: France's most-decorated track athlete Marie-Jose Perec and three-time Olympic gold medal-winning judoka Teddy Riner jointly lit the Paris Olympics cauldron on Friday.

Perec and Riner strode up to the cauldron which formed the base of a hot air balloon in the Tuileries Gardens after it had been transported from the ceremony at the Eiffel Tower by boat and by a succession of French sports figures.

Earlier, French President Emmanuel Macron officially declared open the Paris Olympics, at the end of a spectacular but rain-soaked opening ceremony held for the first time outside the main stadium.

"I declare open the Games of Paris celebrating the 33rd Olympiad of the modern era," said Macron, launching the Games exactly 100 years after Paris last hosted the Olympics.

The opening ceremony of the Olympics in Paris kicked off with frenzy and excitement amid heavy security, following threats of rain and potential sabotage attacks.

A fictional scenario in which the arrival of the Olympic flame goes awry is depicted ahead of an extravagant show on the river Seine that will kick off the summer Games.

French soccer superstar Zinedine Zidane was shown running across Paris to bring the flame, in a pre-recorded video that included him taking it onto the metro.

Moreover, just hours after a sabotage attack on the high-speed TGV rail network, a huge police force was on display in Paris. The attack caused travel chaos across France and put the spotlight on the security risks at a time when all eyes are on the country.

The ceremony features a fleet of barges taking nearly 7,000 athletes on the river, by some of Paris' most famous landmarks.

A giant plume of blue, white and red smoke was sent high above a bridge over the river as the ceremony started.

"We are super excited, it happens once in a lifetime," 17-year-old Elise Boukorrass said.

It had been raining on and off earlier in the evening in Paris and weather forecasters have predicted heavy showers, with one meteorologist even calling it a "disaster" for the open-air ceremony.

"The rain won't stop me from cheering on the Olympics - sport is everything to me and I'd do whatever it takes to watch this," said Flavia Merluzzi, 20, an architecture student.

Lady Gaga sang a French cabaret song near Notre-Dame cathedral and a winged man played accordion.

Amid rumours that Canadian singer Celine Dion could also be part of the show, spectator Chantal Beauvais said it would be "magical" to watch her.

It will be the first time that an opening ceremony has taken place outside a stadium.

— Additional input from Reuters