50 C. postal stamp (2) with overprint in type I as correctly franked multiple franking on cover from "Dunkerque 1.7.40" (first day) to Arneke with reverse arrival stamp from 2.7.40, right stamp top left irregular perforated, cover with hinges otherwise in perfect condition, signed Dr. Dub and photo expertize autumn VP (2014) : "the stamps are only in small number of pieces recorded, so they are very rare. ", Michel 400.-, provenance collection Horst bolder (Fr. 384)