A common fear of the German, by the British, the Russians and the French led them to form an alliance, which was referred to as the Triple Entente. They faced the alliance that was formed between Germany, Italy and Austria-Hungary and in 1914, World War I broke out. A bloody and drawn-out affair, this war lasted four long years and consisted mainly of battles fought in the trenches. The deadlock between the opposing forces was eventually swayed when the United States joined the war in 1917, helping France drive out the Germans.
The Versailles Treaty was drawn up and considerable restitution and payment money was paid by the German to the Allies. The Versailles Treaty imposed very strict measures on Germany, something that brought on humiliation and resentment in the Germans, and which can be considered one of the underlying causes of World War II.
The period between the two world wars saw great advances and progression in artistic, literary and cultural movements, with France a key player in their development and evolution. World War II broke out in 1940 when the Germans invaded Paris, occupying northern and western France for the following four years. The French government in place at the time, Vichy's puppet government, was controlled by Marshal Petain. This government was in favor of returning France to a more traditional, patriotic past. However, a resistance soon began to build up with General Charles de Gaulle at the head of the movement. When the Allies invaded Normandy on June 6, 1944, de Gaulle entered Paris and took over the administration. He was the head of the Fourth Republic.
The postwar years saw great advances with regard to social reform and economic development. French citizens began benefiting from a social security system which provided for health care, pensions for disability and old age, and also unemployment insurance. There was also a lot of consumerism and advancements in technical and industrial fields.