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

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

“We will analyse this in real time,” Mr Macron added.

Any such relocation would be a huge undertaking and would deprive the Paris Olympics of their defining image.

More than 300,000 spectators are expected to attend the ceremony, with a further 200,000 watching from buildings along the Seine.