1 Fr. Charity issue \"marshal F. Foch\" with overprint in type I, variety \"inverted overprint\", properly franked single franking on letter from \"Ghyvelde 8.07.1940\" to Dunkirk with reverse arrival postmark from \"9.07.1940\", faultless preservation, expertise Lothar Herbst VP (2018) : \"the preservation is perfect. The stamps are only in very small number of pieces known, therefore are they very rare, especially stamps with inverted overprint. \", Michel 1.500.-