Maso was born in Toulouse, France. Maso started his rugby career as a rugby league player for XIII Catalan, being the son of the French rugby league internationalist Jep Maso. However, he switched to union. He played club rugby for Narbonne, Toulonnais, and Perpignan. He debuted for France against Italy in Naples in 1966. He also toured Australia, New Zealand and South Africa with the national side, and played three times for the Barbarians.