At five o’clock on the morning of August 7, 1914, French troops launch their first attack of World War I, advancing towards the city of Mulhouse, located near the Swiss border in Alsace, a former French province lost to Germany in the settlement ending the Franco-Prussian War in 1871.
As envisioned by French Commander in Chief Joseph Joffre, the Battle of Mulhouse was intended to anchor the French recapture of Alsace and provide a base for further French operations to the north. Operating according to the Plan 17 strategy—which emphasized offensive warfare above all else as ideally suited to the French temperament and strengths—Joffre sent General Bonneau and his VIIth Corps over the Vosges Mountains, on the frontier between France and Alsace, with bayonets drawn on the morning of August 7. Bonneau’s men captured Altkirch, a town with a population of 4,000 on the way to Mulhouse, in six hours, suffering 100 casualties. The bayonet charge over the crest of the Vosges that morning seemed a symbol of the classic, glorious French spirit and courage, in a war where most of the fighting would be messy, brutal trench warfare.
Finding only suspiciously light German defenses around Mulhouse, Bonneau hesitated after taking Altkirch, wary of stepping into a trap. After an impatient order from French command, however, he moved ahead with the advance. On August 8, French troops entered Mulhouse without firing a shot; the town’s German occupants had already evacuated.
As the French were occupying Mulhouse, German reserve troops were arriving from Strasbourg and deploying around the town, and on the morning of August 9 the Germans mounted a counterattack against nearby Cernay. Though Bonneau’s men fought fiercely throughout the day and overnight to hold their positions, they were overpowered; by the time Joffre had dispatched a reserve division to Mulhouse, the French had begun a slow withdrawal in order to escape being encircled by the Germans. Joffre accused Bonneau of being too tentative and not mounting a sufficiently aggressive offense; he relieved him of the command and replaced him General Paul Marie Pau, who emerged from retirement to command the "Army of Alsace" in its unsuccessful advance on Lorraine later that month.