The 1914 French mobilization was the set of operations at the very start of World War I that put the French Army and Navy in a position for war, including the theoretical call to arms of all Frenchmen fit for military service. Planned long before 1914 (via Plan XVII), each man's assignment was based on his age and residence.
It was triggered in response to equivalent measures taken by Germany, the French mobilization took place over 17 days, from August 2 to 18, 1914, and involved transporting, clothing, equipping and arming more than three million men in all French territories, both in metropolitan France and in some of the colonies, and then transporting them by rail to the potential theater of war, which at the time was considered to be the Franco-German border.
Such event had political (Sacred Union), socio-economic (due to the departure of almost all young men) and, of course, military consequences (the start of the Battle of the Frontiers). It was the first time that a general mobilization was declared in France (in 1870, only the professional army was mobilized); the second took place in 1939. In August 1914, 3,780,000 men were mobilized; in total, throughout the war, some 8,410,000 French soldiers and sailors were mobilized, including 7% indigenous soldiers.