25 C. Postal stamp "Merkur head" and 75 C. Postal stamp "Paul Doumer" with overprint in type I, properly franked mixed franking on cover from Dunkerque 2.07.1940 to Ghyvelde with on the back arrival stamp from 3.07.1940, faultless condition, expertise Lothar Herbst VP (2019) : "the condition is perfect. The stamps are only in very small number of pieces known, therefore are they very rare. ", Michel 1.700.-