45 C. Postage stamps issue "Merkur head" and 55 C. Special edition "Jean de la Fontaine" with hand stamp overprint in type I, properly franked mixed franking on letter from "Dunkerque 21.07.40" to Ghyvelde with on the back arrival stamp from 22.07.1940, faultless condition, unsigned, expertise Lothar Herbst VP (2018) : "the condition is perfect. The stamps are only in very small number of pieces known, therefore are they very rare. ", Michel 1.100.-;