Germany War II in Europe. In response to Hitler's actions, two days later, on 3 September, after a British ultimatum to Germany to cease military operations was ignored, Britain and France declared war on Germany. In the spring of 1940, Germany conquered Denmark and Norway, the Netherlands, Belgium, Luxembourg, and France forcing the French government to sign an armistice after German troops occupied most of the country. The British repelled German air attacks in the Battle of Britain in the same year. In 1941, German troops invaded Yugoslavia, Greece and the Soviet Union. By 1942, Germany and other Axis powers controlled
France–Germany relations “phony war”. When the Germans launched their blitzkrieg invasion of France in 1940, the French Army crumbled within weeks, and with Britain retreating, an atmosphere of humiliation and defeat swept France. A new government under Marshal Philippe Pétain surrendered, and German forces occupied most of the country. A minority of the French forces escaped abroad and continued the fight under General Charles de Gaulle (the “Free French” or “Fighting French”). On the other hand, the French Resistance conducted sabotage operations inside German-occupied France. To support the invasion of Normandy of 1944, various groups increased their sabotage and guerrilla attacks; organizations