From 1874 to 1880, General Raymond Adolphe Séré de Rivières oversaw the construction of the Séré de Rivières system, a line of fortresses long from Belfort to Épinal and another line long from Toul to Verdun, about from the Franco–German border. The River Meuse flows northwards from Toul to Verdun, Mézières and Givet on the Belgian border and there is a tributary of the Moselle between Belfort and Épinal, the rivers running near parallel to the 1871–1919 Franco–German border. A wide interruption in the French fortifications was left between Épinal and Toul, known as the Trouée de Charmes, which was west of Nancy, about from the Franco-German frontier. A second series of fortifications, to prevent the main line being outflanked, was built in the south from Langres to Dijon and in the north from La Fère to Rheims, then from Valenciennes to Maubeuge, although for financial reasons these took until 1914 to complete.
Prelude
The French had suffered a crushing defeat in the Battle of Lorraine and were retreating in disorder. The situation left Helmuth von Moltke the Younger, the Chief of the General Staff of the German army, with a difficult choice. The apparent collapse of the French Second Army made possible a breakthrough at the Trouée de Charmes and the encirclement of all French troops in Lorraine and the Ardennes. Moltke decided to pursue the French and to break through the trouée. He maintained the left wing at its full strength of 26 divisions and ordered the Bavarian 6th Army to attack at the junction of the French Second and First armies. Castelnau, whose Second Army was regrouping in the Trouée de Charmes area, learned from the Deuxième Bureau, that German columns were moving to Saffais and Bechamps and heading for the gap and a few hours later French aerial observers spotted the German troops. Joseph Joffre, the French Commander in Chief, directed General Dubail to reinforce the Second Army with the VIII Corps.
Battle
On 24 August, the Bavarian 6th Army began to attack in the direction of the "Trouée de Charmes" against the centre of the Second Army, as this was judged to be where the French were the strongest. Initially the Germans were successful and managed to take Damelevières and Gerbéviller, then pushed the French from Vacquenat Wood, Clairlieu and Censal, from where they moved towards Bayon. The Second Army was able to limit the German advance, the French 74th Infantry Regiment in particular, fighting with great tenacity and Bavarian attacks on the Flainval plateau were repulsed. To force through the gap, the 6th Army moved troops to the centre from the flanks, which Castelnau exploited by attacking the German flanks with the 71st Division and they were pushed out of Erbeviller, Réméréville and Courbesseaux. The right wing of the Second Army attacked Rupprecht's left flank and managed to take Saint-Boingt, Essey-la-Côte, Clézentaine and Ménarmont. During the night of the French continued a bombardment and Castelnau concentrated the Second Army against the centre of the 6th Army and launched an early morning attack to take Rozelieures, the attack succeeded but the Germans counter-attacked and retook Rozelieures. Castelnau now again attacked both German flanks with the XV Corps and XVI Corps. This had a devastating effect on the morale of the Bavarians, who had expected to be in pursuit of a defeated enemy. The Bavarian centre was kept under constant artillery fire by the French, and at the French regained Rozelieures from the 6th Army, which suffered casualties of 2,500 men killed; on 26 August, Rupprecht ordered a retreat.
Aftermath
The Battle of the Trouée de Charmes was a victory for the French Second Army; in stopping the Germans from passing through the Trouée de Charmes, Castelnau possibly saved the French from disaster, The two sides regrouped and on 4 September, fought the Battle of Grand Couronné when the Germans tried to capture Nancy but they had to abandon their effort on 13 September; the front line in Lorraine remained quiet for the next four years.
