He was one of the few French military who was not discouraged by the capitulation of France. Initially, he and just a few followers decided to continue the struggle from England. Later on he received more and more support; as the leader of the Free French he managed to free the colonial empire from the Vichy regime and he made France one of the larger Allied powers.
In May of 1940, Jacques-Philippe Leclerc managed to escape German captivity. He joined the Free French [France Libre] forces of Charles de Gaulle and liberated Paris in August 1944. That made him one of the best known generals in the Second World War.