Despite reputable speed and solid technical expertise, Manzon's results in races were often disappointing due to a lack of mechanical reliability. In six participations at the 24 Hours of Le Mans, the French driver never crossed the finish line, always let down by mechanical issues.

Between 1950 and 1952, Manzon shared the wheel of a Gordini with another musketeer: in order, Trintignant, Simon and Behra. It was with the latter that Manzon reached his moment of glory, maintaining the lead over the Talbots and Mercedes for nearly half the race. The Gordini T 15S was leading the race with a lap in advance when Manzon had to return to the pits with brake problems.

After having lost a wheel several times in F1, the French driver gave up on Gordini and took the start at the 24 Hours of Le Mans with a Lancia (Louis Chiron) in 1953 and a Ferrari (Louis Rosier) in 1954. Engine issues in '53 and gearbox trouble in '54 ended Manzon's hopes for success. He returned once to La Sarthe in 1956 with an aging Gordini T15S, the clutch of which quickly gave in.

Manzon ended his motorsports career in 1956 to focus on his Renault dealership. In 2013, on behalf of the Automobile Club de l'Ouest and the 24 Hours of Le Mans Drivers' Club, he received a Hall of Fame jacket as a reward for the spirit and efforts of a driver who played his part the 24 Hours of Le Mans legend.

The Automobile Club de l'Ouest extends its sincere condolences to Robert Manzon's friends and family.