Commissioned by the Seine-Saint-Denis department as a carte blanche for the national commemoration of the centenary of the First World War, this work starts from a body of two hundred postcards held in the departmental archives, received or sent by twenty-six towns of the department between 1914 and 1918. Catherine Poncin develops a method intrinsically bound to the archive, linking past and present, individual and collective histories: from the fronts of the cards, from views of war damage and from the illustrated press she builds new compositions, text posters and sound pieces; from the backs she analyses the handwriting and the inks, drawing out phrases and the vocabulary of life at the front. In participatory meetings she assembles with the inhabitants of the department an exquisite corpse drawn from soldiers' writings, and the electro-acoustician Jean-Louis Dhermy takes hold of the voices to make a song.