30 C. Postage stamps issue \"Merkur head\" (2) and 40 C. Special stamps issue \"world exhibition 1937 in Paris\" with overprint \"Occupied area North France\" in type I, properly franked mixed franking on cover from \"Ghyvelde 21.07.1940\" to Dunkerque with arrival postmark on the back from 22.07.1940, faultless condition, expertized Roumet among others as well expertise Lothar Herbst VP (2023) : \"the condition is perfect. The stamps are only in very small number of pieces known, therefore are they very rare. \", Michel 1.000.-