50 C. postage stamp "Mercury head", vertical pair from the lower left corner with plate number "38149" with overprint "Occupied Territory Northern France" in Type I, variety "inverted overprint - top to bottom", appropriate postage on a letter from "Ghyvelde 14. 07. 1940" to Dunkerque with a rear arrival stamp dated 15. 07. 1940, rare, examined by Calves, Dreyfuss, Roumet and expertise by Lothar Herbst VP (2023) "The condition of the stamps is flawless. The stamps are known in very small quantities, therefore they are rare, with inverted overprint even rarer.", not listed by Michel.