10 C. stamp "Mercury head" and 90 C. stamp "Allegory of Peace" with overprint in Type I, postal franking on a letter from "Dunkerque 18. 07. 1940" to Ghyvelde with arrival postmark on the reverse side dated "19. 07. 1940", flawless condition, expertise by Lothar Herbst VP (2018): "The condition is flawless. The stamps are known in very small quantities, therefore they are very rare.", Michel 800.-