The rôle of the French army, which was operating to the right of the British army, was threefold. It had to support the British attacking on its left. It had on its right to support the center, which, from September 7th, had been subjected to a German attack of great violence. Finally, its mission was to throw back the three active army corps and the reserve corps which faced it.
On the 7th, it made a leap forward, and on the following days reached and crossed the Marne, seizing, after desperate fighting, guns, howitzers, mitrailleuses, and a million cartridges. On the 12th it established itself on the north edge of the Montagne-de-Reime in contact with the French center, which for its part had just forced the enemy to retreat in haste.
The French center consisted of a new army created on August 29th and of one of those which at the beginning of the campaign had been engaged in Belgian Luxemburg. The first had retreated, on August 29th to September 5th, from the Aisne to the north of the Marne and occupied the general front Sezanne-Mailly.
The second, more to the east, had drawn back to the south of the line Humbauville-Château-Beauchamp-Bignicourt-Blesmes-Maurupt-le-Montoy.
The enemy, in view of his right being arrested and the defeat of his enveloping movement, made a desperate effort from the 7th to the 19th to pierce the French center to the west and to the east of Fere-Champenoise. On the 8th he succeeded in forcing back the right of the new French army, which retired as far as Gouragançon. On the 9th, at 6 o’clock in the morning, there was a further retreat to the south of that village, while on the left the other army corps also had to go back to the line Allemant-Connantre.
Despite this retreat General Foch, commanding the army of the center, ordered a general offensive for the same day. With the Morocco division, whose behavior was heroic, he met a furious assault of the Germans on his left toward the marshes of Saint Gond. Then with the divisions which had just victoriously overcome the attacks of the enemy to the north of Sezanne, and with the whole of his left army corps, he made a flanking attack in the evening of the 9th upon the German forces, and notably the guard, which had thrown back his right army corps. The enemy, taken by surprise by this bold maneuver, did not resist, and beat a hasty retreat. This marked Foch as the most daring and brilliant strategist of the war.
On the 11th the French crossed the Marne between Tours-sur-Marne and Sarry, driving the Germans in front of them in disorder. On the 12th they were in contact with the enemy to the north of the Champ de Châlons. The reserve army of the center, acting on the right of the one just referred to, had been intrusted with the mission during the 7th, 8th, and 9th of disengaging its neighbor, and it was only on the 10th that being reinforced by an army corps from the east, it was able to make its action effectively felt. On the 11th the Germans retired. But, perceiving their danger, they fought desperately, with enormous expenditure of projectiles, behind strong intrenchments. On the 12th the result had none the less been attained, and two French center armies were solidly established on the ground gained.
MARSHAL FERDINAND FOCH, COMMANDER-IN-CHIEF OF THE ALLIED ARMIES
The crushing defeat of the armies of the Central Powers is due in large measure to the remarkable strategy and superb leadership of this great French soldier.