Alsace & Lorraine
The first French attack of the war, known as the Battle of Mulhouse was fought on 7 August. It began in the south when the French VII Corps, along with 2 infantry and 1 cavalry division, advanced into southern Alsace with the objective of seizing the towns of Mulhouse and Colmar. Mulhouse was taken without a fight on 8 August, causing enormous celebrations in France, however a German counterattack commenced on 9 August, forcing the French to begin a slow withdrawal which was finished the next day. Joffre sent a division to reinforce the attacking force, but it arrived too late to prevent the fall of Mulhouse. In response to the repulse of VII Corps and the other divisions, Joffre sent four additional divisions to form the "Army of Alsace" under the command of retired general Paul Pau.
The main French offensive in the south, known as the Battle of Lorraine, began on 14 August when the First Army of General Auguste Dubail advanced on Sarrebourg while the Second Army of General de Castelnau headed towards Morhange. The French moves were welcomed by the German Sixth and Seventh Armies under the combined command of Crown Prince Rupprecht — Rupprecht was in charge of the German forces assigned to meet and engage the French assault in the centre until they could be enveloped by the encircling German right wing. The German rearguards, equipped with machine guns, inflicted heavy casualties on the French infantry, still wearing their 19th-century style uniform of blue coat and red trousers.
Crown Prince Rupprecht, dissatisfied with the defensive role assigned to him, petitioned his superiors to allow him a counter-offensive. This ran counter to the overall German plan of luring the French in, but on Rupprecht's repeated insistence the policy of defense in the centre was abandoned and a counter-offensive launched on 20 August against the French Second Army which was thrown back into France. This left the French First Army's flank in the air, forcing it to withdraw as well. Pau's Army of Alsace also had to pull back, despite having retaken Mulhouse. By 22 August, the French forces were back on their start lines along the Moselle River.
The Schlieffen Plan, here and elsewhere on the front, now began to unravel as Crown Prince Rupprecht launched a full-scale offensive between Toul and Épinal, starting on 23 August. However, the French forces were now occupying prepared defences and withstood the German attack, which lasted for four days. German forces locked into Rupprecht's offensive were therefore unavailable for the later fighting on the Marne when they may have proved decisive.
Read more about this topic: Battle Of The Frontiers