10 C. and 90 C. postal stamp with overprint in type I as correctly franked mixed franking on cover from "Dunkerque 16. 7. 40" to Ghyvelde with reverse arrival postmark from 17. 7. 40", signed HBZierer and certificate with photograph autumn VP (2014) : "the condition is perfect. The stamps are only in very small number of pieces recorded, so that they very rare are. ", Michel 1. 000.-