On 12 August 1870, during the war, Bazaine was nominated as the commander-in-chief of the Army of the Rhine, which was forced to unfold towards Châlons-sur-Marne to rejoin reserves in order to face the German troops. On the other hand, while he was presented with the occasion to destroy several enemy army corps following the Battle of Mars-la-Tour (), on 16 August, he decided, to the astonishment of his general staff headquarters to unfold his army of 180,000 men at Metz (), accordingly cutting himself from free France and his reserves. Two days later, at the eve of the Battle of Saint-Privat (), Marshal François Certain de Canrobert requested urgently and for several times reinforcements from Bazaine, but did not obtain them. The latter had judged that Saint-Privat was not an important battle and refused to engage his reserve troops, which were numerous. No reinforcements were sent to the French troops which were engaged heroically in combat on the plateau and Bazaine didn't even appear on the field of battle.