30 C. and 70 C. postage stamps "Mercury Head", with a horizontal hand-stamped overprint "Occupied Territory Northern France" in Type I, on the front of an envelope with cancellation mark "Dunkerque 19. 07. 1940", flawless condition, examined by Roumet, Dreyfuss and expertise by Lothar Herbst VP (2025) "The condition is impeccable.", Michel 500.-