Joffre held the conference of Chantilly from 6 to 8 December 1915 to makes battle plans with his Allied counterparts and to coordinate military offensives for 1916. General Headquarters moved to Beauvais in December 1916, and Chantilly became home to hospitals for soldiers wounded on the front, one in the hôtel Lovenjou, the other in the Egler Pavilion. One of the three camouflage workshops of the French 1st Engineers Regiment opened in 1917 in custom-built barracks on the "petite pelouse" near the racetrack. Up to 1200 women were hired, as well as 200 German prisoners of war and 200 workers from Annam in French Indo-China (then a French protectorate). They painted canvases which the army used to mask artillery and troop movements from view.