Olympic gold medallist Camille Muffat was amongst ten people killed when two helicopters collided whilst filming a TV show in Argentina.
Yachtswoman Florence Arthaud and Olympic boxer Alexis Vastine also died in the crash, according to the BBC.
The helicopters were filming popular French TV show ‘Dropped’, a Survivor-style reality program.
Associated Press reports say the crash occurred in La Rioja province, around 730 miles from Buenos Aires.
La Rioja Secretary of Security Cesar Angulo said the cause of the crash was currently unknown.
“An explosion occurred and it’s believed that they must have collided,” Angulo said.
“Aeronautical experts will have to determine that,” he added.
Former Arsenal footballer Sylvain Wiltord, a contestant on the show, tweeted: “I’m sad for my friends, I’m trembling, I’m horrified, I have no words, I do not want to say anything.”
— Sylvain Wiltord (@sylwiltord) March 10, 2015
Muffat retired from swimming last year at the age of 24.
Argentine website La Rioja es Noticia published the names of those who died in the crash:
Camille Muffat, Olympic swimmer
Alexis Vastine, Olympic boxer
Florence Arhaud, sailor
Juan Carlos Castillo, helicopter pilot
Roberto Abate, helicopter pilot,
Laurent Sbasnik, filming
Lucier Mei-Dalby, filming
Volodia Guinard, filming
Brice Guilbert, art direction
Edouard Gilles, sound