Third Republic of France (World War I)

France entered World War I because Russia and Germany were going to war, and France honored its treaty obligations to Russia. Decisions were all made by senior officials, especially president Raymond Poincaré, Premier and Foreign Minister René Viviani, and the ambassador to Russia Maurice Paléologue. Not involved in the decision-making were military leaders, arms manufacturers, the newspapers, pressure groups, party leaders, or spokesman for French nationalism.

Britain wanted to remain neutral but entered the war when the German army invaded Belgium on its way to Paris. The French victory at the Battle of the Marne in September 1914 ensured the failure of Germany's strategy to win quickly. It became a long and very bloody war of attrition, but France emerged on the winning side. French intellectuals welcomed the war to avenge the humiliation of defeat and loss of territory in 1871. At the grass roots, Paul Déroulède's League of Patriots, a proto-fascist movement based in the lower middle class, had advocated a war of revenge since the 1880s. The strong socialist movement had long opposed war and preparation for war. However, when its leader Jean Jaurès, a pacifist, was assassinated at the start of the war, the French socialist movement abandoned its anti-militarist positions and joined the national war effort. Prime Minister René Viviani called for unity in the form of a "Union sacrée" ("Sacred Union"), and in France there were few dissenters.

A state of emergency was proclaimed and censorship imposed, leading to the creation in 1915 of the satirical newspaper Le Canard enchaîné to bypass the censorship. The economy was hurt by the German invasion of major industrial areas in the northeast. Although the occupied area in 1914 contained only 14% of France's industrial workers, it produced 58% of the steel and 40% of the coal. In 1914, the government implemented a war economy with controls and rationing. By 1915, the war economy went into high gear, as millions of French women and colonial men replaced the civilian roles of many of the 3 million soldiers. Considerable assistance came with the influx of American food, money and raw materials in 1917. This war economy would have important reverberations after the war, as it would be a first breach of liberal theories of non-interventionism. The damages caused by the war amounted to about 113% of the Gross Domestic Product (GDP) of 1913, chiefly the destruction of productive capital and housing. The national debt rose from 66% of GDP in 1913 to 170% in 1919, reflecting the heavy use of bond issues to pay for the war. Inflation was severe, with the franc losing over half its value against the British pound.

To uplift the French national spirit, many intellectuals began to fashion patriotic propaganda. The Union sacrée sought to draw the French people closer to the actual front and thus garner social, political, and economic support for the soldiers. After the French army successfully defended Paris in 1914, the conflict became one of trench warfare along the Western Front, with very high casualty rates. It became a war of attrition. Until spring of 1918, amazing as it seems, there were almost no territorial gains or losses for either side. Georges Clemenceau, whose ferocious energy and determination earned him the nickname le Tigre ("the Tiger"), led a coalition government after 1917 that was determined to defeat Germany. Meanwhile, large swaths of northeastern France fell under the brutal control of German occupiers.