In French service the series saw action during the Battle of France, and post-armistice within both the Vichy French "Armée de l'air de l'Armistice", and the Free French "Forces Aériennes Françaises Libres". On 20 May 1940, the light bomber variant, the Potez 633, took part in a ground attack against German troops near Arras. Three 633s took part in the attack. This was the type's only operational mission over France as two days later the 633 was withdrawn from front-line service. The day/night fighter variant, the Potez 631, had quickly proved to be an ineffectual interceptor; it was slower than some German bomber aircraft and 130 km/h slower than the Messerschmitt Bf 109 E-variant fighter. Perhaps the most successful unit operating the Potez 631 was the "Flottille F1C" of the French Naval Air Arm. Between 10–21 May 1940, aircraft of the "flottille" shot down 12 enemy aircraft in exchange for 8 of their own losses prior to its withdrawal from active combat. The reconnaissance variants, the Potez 637 and 63.11, equipped numerous "Groupes de Reconnaissance" of the French Air Force, with more than 700 reconnaissance Potez 63.11s having been delivered.