French President Emmanuel Macron on Monday praised the diver who embarrassingly crashed into the water in front of the head of state during the inauguration of the Olympic pool, while quipping that he "felt bad for your butt."

Alexis Jandard, a two-time world championship medallist, became a social media sensation when he fell on the diving board and crashed into the water in front of Macron at the opening early this month of the aquatics centre for the 2024 Paris Olympics.

After the mishap he took to social media to mock his own misfortune and then made clear he was targeting a podium place this summer, winning widespread praise.

On Monday, Jandard made a surprise appearance by video link at the end of Macron's interview with broadcasters BFMTV and RMC.

"I felt bad for your butt and your lower back, if I may say so," a smiling Macron told Jandard during their exchange.

Jandard, performing a synchronised routine on the 3 metre board with two other divers during the ceremony, lost his footing while jumping, landed painfully on the board on his back and bottom and then splashed into the water.

The French president praised the 26-year-old diver's ability to laugh at himself and can-do attitude.

"The reaction you had was absolutely perfect," Macron said.

"To take it with humour and above all to immediately get the ball rolling again by saying, 'I know how to salvage the indignity, I'm going to go and get the medal'," Macron said.

A beaming Jandard said that from the point of view of promoting the "wonderful" swimming pool in the aquatics centre, his mission was a "success."

"We've succeeded in our mission and now we just have to get on with the job, keep working to show ourselves in a better light", said Jandard.

Jandard, a reservist in France's police force, is to compete in Paris in the 3-metre synchronised event.