This breaks from the tradition of the Games opening in the main stadium.

In the event of a threat, Macron said, instead of teams sailing down the Seine on barges, the ceremony could be “limited to the Trocadero” building across the river from the Eiffel Tower or “even moved to the Stade de France”.

But with war raging in Ukraine and in Gaza, the ceremony also leaves teams potentially vulnerable to attack – French authorities have, for example, mentioned the possibility of an attack launched by drones.

So far, organisers have denied the ceremony on July 26 could be moved to a different venue if authorities believe there is a possibility it will be targeted.

“This opening ceremony … is a world first. We can do it and we are going to do it,” Macron said in an interview with BFMTV and RMC.

But, he added, “there are Plan Bs and Plan Cs”, including moving the ceremony to the Stade de France to the north of Paris, the main stadium for the Olympics where the rugby sevens and athletics will be held.

Having the ceremony in the main stadium “is what happens traditionally”, Macron said. “We will analyse this in real time,” he added.

Moving the ceremony from the Seine would be a huge undertaking and would deprive the Paris Olympics of their defining image.

More than 300,000 spectators are expected to be present for the ceremony, with another 200,000 watching from buildings along the Seine.

The French government also decided that tourists will not be given free access to watch the opening ceremony because of security concerns. Free access will be invitation-only instead.

So far, all countries have said they plan to take part in the open-air river parade, including the most risk-averse such as the United States and Israel.

“We have anticipated, we have put in place a security cordon which is going to be very big, where we are going to check all the people coming in and going out,” Macron said.

He also said he would do “everything possible” to have an Olympic truce during the Games.

The truce is an historic tradition that peace reigns during the Olympics.

“We want to work towards an Olympic truce and I think it is an occasion for me to engage with a lot of our partners,” he said.

He said he would ask the Chinese president, Xi Jinping, to help him in that aim when he visits Paris in early May.

“The Chinese president is coming to Paris in a few weeks, and I’m going to ask him to help me,” Macron said. “This is a diplomatic moment of peace.”

Macron also backed the decision to allow Russian athletes to compete in the Olympics despite the Ukraine invasion, but under a neutral flag.

Additionally, he defended the participation of Israeli athletes under their country’s flag despite its offensive in Gaza in which 33,000 Palestinians have been killed and hundreds of thousands have been displaced.

“We cannot say that Israel is attacking,” Macron said. “Israel was a victim of a terrorist attack to which it is now responding to in Gaza.”

The Paralympics take place after the Olympics, beginning on August 28.

Macron said he had a target of France finishing in the top five in the medals table for the Olympics and among the top eight nations for the Paralympics.

The president admitted the Paris metro system was not accessible to wheelchair users, which could pose difficulties for spectators at the Paralympics.

Macron admitted that on many of the older metro lines there was “not enough” accessibility.

To compensate, he said, 1,000 taxis with wheelchair access would be made available for the duration of the Paralympics.