After receiving his diploma in 1912, Charles studied with Carl Flesch in Berlin and Lucien Capet at the Conservatoire de Paris. He was conscripted into the German army in World War I, serving as a sergeant gunner. He was gassed at Péronne and wounded at Verdun. Though most of his career was accomplished in France and in the United States, Munch considered that "as an Alsacian and as a musician, [he was] purely and profoundly German, but that [he was] a friend of many countries and first and foremost a musician and a conductor".