BURO+ (Av. Gabriel Péri) is the only place in Grenoble where to print a poster the saturday.
Ask for a devis at COREP (Contact: grenoble@corep.fr, 2 Rue du Tour de l'Eau, 38400 Saint-Martin-d'Hères, providing the type of paper (MAT 180G, BRILLANT 200G, TISSU, BACHE)