The 20th Grand Prix de la Marne was a non-championship Formula Two motor race held on 29 June 1952 at the Reims-Gueux circuit. It was the fourth round of the 1952 Les Grands Prix de France championship. Race distance was decided not by distance but by time, the duration being 3 hours. The race was won by Jean Behra driving a Gordini Type 16. Giuseppe Farina was second in a Ferrari 500, and his teammates Alberto Ascari and Luigi Villoresi shared third place, Villoresi's own car having suffered engine failure. Ascari set pole and fastest lap.