Manzon was born on 12 April 1917 in Marseille, France. He began his working life as a mechanic and took up competitive racing after the Second World War, initially in a Cisitalia D46. In 1948 he joined the Gordini team, winning some minor events despite the machinery's chronic unreliability. The team ran small, nimble Simca-based cars — the supercharged 1.5-litre four-cylinder Simca unit made the cars eligible for Formula One events alongside their F2 programme.
When the FIA Formula One World Championship began in 1950, Manzon was a Gordini regular. He made his championship debut at the 1950 Monaco Grand Prix and scored championship points at the 1950 French Grand Prix, where he was classified fourth. His teammate Maurice Trintignant was Gordini's other frontline driver, and the two Frenchmen provided the team's most consistent presence in the results during the first season.
Gordini's programme was run on chronic financial strain. Amedée Gordini maintained his operation through starting money from non-championship events, loans, and the sale of customer cockpits, and the team's inability to keep pace with Ferrari and Maserati in development grew more acute each year. Despite this, Gordini's neat, lightweight cars occasionally punched above their weight, particularly on street circuits and when faster machinery retired.
Manzon's best championship season was 1952, when Gordini ran the new Type 16 with a two-litre six-cylinder engine and the World Championship was run to Formula Two regulations. He finished third at the 1952 Belgian Grand Prix at Spa — his first podium — and placed fourth at the French Grand Prix and fifth in the Netherlands. These results lifted him to sixth in the World Drivers' Championship, the highest standing of his career and the highest a Gordini driver would achieve in the three-year F2-regulation era. At the 1952 Belgian Grand Prix the team's car was considered genuinely competitive on merit.
The 1953 season brought a weakening of the T16's form. Manzon contested the Argentine, Dutch, and Italian rounds without points finishes as Ferrari and Maserati pulled further ahead. Gordini could not fund an adequate development programme under the 2.5-litre Formula One regulations that arrived for 1954.
Manzon departed Gordini at the end of 1953 and joined Louis Rosier's private team, which was campaigning Ferraris. At the 1954 French Grand Prix at Reims, Manzon finished third in a Ferrari 625, his second championship podium. He also drove a Scuderia Ferrari-entered 553 at the 1954 Swiss Grand Prix, though he did not start.
Manzon returned to Gordini for 1955 and 1956. In World Championship events results were sparse; the team's ambitious new T32 with its straight-eight 2.5-litre engine proved too heavy to be competitive despite its technical interest. Outside the championship, Manzon won the 1956 Naples Grand Prix at Posillipo — a win that came after the Ferraris faltered mid-race, a pattern that recalled his 1952 Belgian victory — and took a sports car victory at Pescara that same year. When Gordini finally ran out of funding and closed his racing operation after two 1957 appearances at Pau and Naples, Manzon's championship career was over.
After retiring from racing, Manzon established and operated a diesel equipment distribution business in the south of France. He died near Cassis on 19 January 2015, aged 97. At his death he was the last surviving driver from the six-race 1950 World Championship series, a connection to the opening round at Silverstone on 13 May 1950 that made him a unique figure in the sport's lineage. No other driver from the first championship season outlived him. He was also among the last survivors of the entire formative period during which the Gordini team — running underfunded against the Italian factory marques — nonetheless produced the sport's dominant French-speaking presence for most of a decade.