Initially the strongest of all the Allied armies, France's metropolitan and colonial units bore the greatest burden during the first two years of the Great War, and made a great contribution to the final victory.

In common with most European countries, the pre-war French Army was based on a system of national military service providing conscripts who could be subject to recall as reservists for several years after. However, the advent of war, the crisis in manpower, and the development of new tactics and weapons brought radical changes. The influence of these factors on the organisation, equipment, uniforms and tactics of the French Army during World War I is examined in detail in this concise text.