De Gaulle commanded an armored Division in combat from May 12th 1940 to June 7th 1940. Less than a month. Afterwards he was appointed to a political position, and remained a political leader for the rest of the war.

His performance as a division commander wasn't brilliant, and his armored division did not coordinate it's infantry and armor components well. However, it's probably unrealistic to expect such a performance since his division had little time to train as a division. His division fought hard in two battles (Montcornet and Abbeville) and inflicted casualties, but ultimately did not achieve their objectives. De Gaulle's division probably fought better than most French divisions in 1940, but that's damning with faint praise. Other French generals who had even worse results in May 1940 (LeClerc, Juin) were quite successful later in the war. Perhaps de Gaulle would have been as well if he had had more than 26 days as a general in combat.