Anniversary of the Battle of Mars-la-Tour, 16 August 1870, (1892). The Battle of Mars-La-Tour was fought on 16 August 1870 during the Franco-Prussian War near the town of Mars-La-Tour in north-east France. Two Prussian corps encountered the entire French Army of the Rhine, and successfully forced the Army of the Rhine to retreat into the fortresses of Metz. A print from the Le Petit Journal, 3rd September 1892.