Swiss police have said the fatal wingdiving accident occurred among a group who were in the region as guests of a company that makes extreme sport films for the internet.
Although police have yet to confirm the victim's identity, he is understood to be Olympic stuntman Mark Sutton.
Police, though, said: "The victim, a Briton, was 42 years old. He was staying in Chamonix (in France) with 20 followers, considered among the best in the world in this discipline."
More top news
The son Cecil the lion, whose 2015 killing prompted an international outcry, has also been fatally shot during a hunt.
Thickening cloud and rain stalling across Wales and southwest England through tomorrow
A parole board in Nevada, USA, decided that the 70-year-old former football, TV and movie star can be released in October.