This is French Observer's Brevet, B 4000 with a Carte Postale or postcard photo of Charles-René Drouard, dedicated on the reverse "Le 22 Juillet 1918.  En Souvenir a ma chere petite Cousine le 22/7/1918. Drouard Charles." Mobilized on 23-August-1914, Drouard was assigned to the 51st Artillery from which he passed into aviation on 3-July-1915 becomming at first an observer.  He received 4 citations, 1-November-1915 (corps) and 27-July-1916, 22-July-1917 and 9-November-1917 (Armee) and specifically mentioned in this last citation - by now a sous-lieutenant with Escadrille F. 208 - for a tenacious combat on 29-April-1917.  He was elevated to Pilote and in the Spring of 1918 flew with Escadrille 78, passing from that unit to Escadrile Br 231 on 6-June-1918 and then becomming that unit's CO as a Lieutenant on 1-July-1918.  He remained in that position until the end of September when he was hospitalized.  After the war he completed his degree at the École polytechnique in Paris in 1920 and served in various high positions with the Ministry of Mines, passing away in 1978 at age 84. Drouard was one of eight aviators (including the ace, Alfred Heurtaux) from Nantes included in an exhibit « Les aviateurs nantais dans la Grande Guerre » held 10 April to 18 May 2018.