On July 15 the Germans launched their final great attack of the war, the blow falling between Château-Thierry and Reims. The French Armies involved in this battle were holding the following sectors:
(i) The Tenth Army, between the Aisne and the Ourcq.
(ii) The Sixth Army, between the Ourcq and the Marne.
(iii) The Fifth Army, between the Marne and Reims.
(iv) The Fourth Army, east of Reims.
The warning order to concentrate his units was received by the G.O.C., French Tank Corps, on July 14. At that time the G.O.C. Tenth French Army had at his disposal five heavy battalions and three light, and the Fifth and Sixth French Army respectively now received one heavy and three light battalions. The total number of tank battalions available was, therefore, seven heavy battalions and nine light ones.
The main attack was to be made by the Tenth French Army, whilst the Sixth and Fifth Armies were to intervene, when the time was ripe, in order to harry the enemy in a retirement which would be inevitable if the attack of the Tenth Army was successful. The entire operation was to be based on tanks, which were to be engaged to the last machine. As this was the greatest French tank battle fought during the war it is interesting to enter, in some detail, into the operations of the tanks allotted to the French Tenth Army.
On July 14, when orders were issued for the concentration of tanks on the Tenth French Army front, Colonel Chedeville, commanding the 2nd Tank Brigade, was with the Third French Army. He had at his disposal three St. Chamond battalions, the 10th, 11th, and 12th, two Schneider battalions, the 3rd and 4th, and one complete Light Brigade comprising the 1st, 2nd, and 3rd Renault battalions, and the 1st Schneider battalion. Of these the first five were in the First and Third French Army areas, and had suffered severely in the counter-attack of June 11. Having received his orders, Colonel Chedeville at once assembled his battalion commanders and explained to them the situation. At 6 p.m. a further conference was held at which the proposed sectors of attack were allotted for reconnaissance. These reconnaissances were completed by 6 p.m. on the following day, and on them was based “Army Operation Order No. 243,” in which tank units were allotted as follows:
| 1st Corps | |
| 3rd Heavy Tank Battalion (27 tanks). | Allotted to 153rd Division. |
| XXth Corps | |
| 12th Heavy Tank Battalion (30 tanks) | Allotted to 2nd American Division, |
| 11th Heavy Tank Battalion (30 tanks) | „ „ 2nd American Division. |
| 4th Heavy Tank Battalion (48 tanks) | „ „ Moroccan Division. |
| 1st Heavy Tank Battalion (48 tanks) | „ „ 1st American Division. |
| XXXth Corps | |
| 10th Heavy Tank Battalion (24 tanks) | Allotted to 38th Division. |
| In Army Reserve in the region of Villers-Cotterets—Fleury | |
| 1st Light Tank Battalion (45 tanks) | |
| 2nd Light Tank Battalion (40 tanks) | |
| 3rd Light Tank Battalion (45 tanks) | |