We trace how France, despite emerging victorious from World War I, was left weakened by economic struggles, a decimated workforce, and a neglected military. As Germany rearmed in defiance of the Treaty of Versailles, France’s attempts to counter the Nazi threat were thwarted by political divisions, including anti-Semitic opposition to Prime Minister Léon Blum, and by British foreign policy focused on containing the Soviet Union rather than confronting fascism. At key junctures—such as the remilitarization of the Rhineland and the appeasement at Munich—France and its allies hesitated, missing crucial chances to halt Hitler’s aggression. We’ll discuss how these decisions, alongside strategic miscalculations like the flawed reliance on the Maginot Line and the poorly timed deployment of reserves, led not only to France’s swift fall in 1940 but also to the spread of Nazi atrocities across Europe.