Béart was born Guy Béhart-Hasson (originally spelled Béhar-Hassan) in Cairo, Egypt,[1][2] to a Sephardic Jewish family, that later sought refuge in Lebanon during his childhood.

[3][4][5][6][7][8] His father's work as an accountant and business consultant saw the family move frequently, leading to a childhood spent in France, Greece, and Mexico, in addition to Egypt.

When his father died in 1952, the young Béhart chose to pursue a career in engineering in order to help support his family, studying at the prestigious École nationale des ponts et chaussées.

Taken under the wing of renowned music producer Jacques Canetti and fellow musician Boris Vian, he released an album of his own, which won the prestigious Grand Prix de l'Académie du Disque français in 1958.

He continued to perform at a variety of venues around the country and in 1999 did a five-week run at Bobino in Montparnasse that was so popular it allowed for a successful re-release of his double live album recorded at the Olympia.