Who lead the french army in world war 1?

Joseph Joffre was Commander-in-Chief, a position he had held since 1911. While serving in this position, Joffre was responsible for development of the Plan XVII blueprint for the invasion of Germany, which proved unsuccessful. Joffre was thought to be the 'Savior of France' due to his serenity and a refusal to admit defeat, valuable at the beginning of the war, along with his regrouping of retreating allied forces at the Battle of the Marne.