on 10 May 1940, the division was alerted for movement into Belgium under the Dyle Plan. Assigned to the 4th Army Corps of the 1st Army, the 15e DIM recalled the 27th Infantry Regiment, which was at Sissonne on maneuvers. The 134th Infantry Regiment was sent ahead to Saint-Quentin, while the 4e GRDI was detached to the corps headquarters as part of Groupement Arlabosse, led by its commander. On the next day the division moved by road from Chauny to Gembloux through Tergnier, Saint-Quentin, Le Cateau, Binche, La Louvière, Gosselies, and Tongrinne, setting up its headquarters at Tongrinne. The 4th and 134th Infantry Regiments began moving into positions on 12 May, with a battalion from each regiment occupying the sector of the 1st Moroccan Division, which had not yet arrived, from Ernage to the northern part of Gembloux. Groupement Arlabosse was briefly transferred back to the division that day but again detached to the 1st Moroccan Division at noon. The 27th Infantry Regiment arrived at the division positions on 13 May and at the end of that day the division was relieved by the newly arrived 1st Moroccan Division. Its positions shifted to a sector between the 1st Moroccan Division on the southern edge of Gembloux and the 12th Motorized Infantry Division at Beuzet; the 134th Infantry held the northernmost part of the line, the 27th Infantry the middle, and the 4th Infantry the southernmost. At noon on the same day the 4e GRDI was placed under direct corps command between Geest and Noville to the north of Grande-Rosiére. The division engaged German forces along its front on 14 May, while being forced to retreat in what became known as the Battle of Gembloux. Its artillery targeted German tank concentrations in the area of Grandleez and Baudeset in support of the 1st Moroccan Division. German tank attacks were repulsed by the 27th Infantry Regiment to the south of Gembloux and the 4th Infantry Regiment at Beuzet on 15 May. On that day the 13e Battalion de Chars de Combat with Hotchkiss H35 light tanks of 515e Groupe de battalions de Chars de Combat was attached to the division, while the 1st Battalion of the 27th Infantry Regiment was detached to Groupement Bougrain. During the night it retreated under orders by rail to Wavre and Charleroi. The division headquarters shifted to Thiméon on 16 May, when it held defensive positions on