50 C. Postal stamp \"Merkur head\", vertical pair from corner margin lower left with sheet number \"38149\" with overprint \"Occupied area North France\" in type I, variety \"inverted overprint - top down\", properly franking on cover from \"Ghyvelde 14.07.1940\" to Dunkerque with arrival postmark on the back from 15.07.1940, rare, expertized Calves, Dreyfuss, Roumet and expertise Lothar Herbst VP (2023) \"the condition of the stamps is perfect. The stamps are only in small number of pieces known, therefore are they rare, with inverted overprint rare. \", Michel not listed.