30 C. Postage stamps issue "Aristide Briand" and 70 cent charity issue "Births decline" with hand stamp overprint in type I, properly franked mixed franking on letter from "Dunkerque 04.07.40" to Ghyvelde with on the back arrival stamp from 05.07.1940, 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 1.500.-