The French, with British, Commonwealth and later American assistance, showed the superiority of their military doctrine as reformed by various presidential decrees since the Franco-Prussian War of 1871 when they managed to hold on for four years and defeat the Germans in World War I. After major conflicts such as the Battle of the Frontiers, the First Battle of the Marne, the Battle of Verdun, and the Second Battle of the Aisne, resulting in tremendous loss of life, bitterness and mutiny within the army, the French proved themselves to be enough of a cohesive fighting force to counterattack and defeat the Germans at the Second Battle of the Marne, the first in what would become a string of Allied victories that ended the war .... the Treaty of Versailles eventually returned Alsace-Lorraine to France. http://www.rootschat.com/links/055s/
The French really suffered terribly ....... and also the soldiers that fought from the French Empire ! Four years of war saw 8,660,000 Frenchmen of all backgrounds placed into the blue uniform of the Poilus. The graves of the western front, Gallipoli and Salkonia kept 1,390,000 of these men for all time while another four million took home visible life changing wounds. This figure was augmented by the colonial troops of the extended areas of the empire. During the conflict the French army drew 163,000 Senegalese Tiraillieurs from West Africa, at least 200,000 turbaned spahis cavalry and Zouave infantry from North Africa, and no less than 70,000 Southeast Asians from French Indochina. It is estimated that some 40,000 of these colonial troops lost their lives in the fetid trenches of the French homeland http://militaryhistory.suite101.com/article.cfm/the_french_army_of_1914