Guillaume is a world champion breath-hold diver. He grew up by the sea, in Nice, France. As a child he and his friends would challenge themselves to under-water breath holding competitions.
Under the guidance of Claude Chapuis (Funder: International AIDA Federation) he went become a three-world record holder with a maximum depth to date of 410 feet (125m). Amoung other films, in 2010 he successfully produced the film Free Fall, with with his partner Julie Gautier, in which he dived off the seabed into the Deans Blue Hole (Bahamas).
Guillaume currently teaches deep diving at his school CIPA, in Nice.