50 cent special stamp "a hundred years membership Algeriens to France", block of four with shifted hand stamp overprint in type I as well additional centered over both stamps hand stamp overprint in type I, correctly franked multiple franking on cover from "Ghyvelde 21.07.1940" to Dunkerque with on the back arrival stamp from 22.07.1940, expertise Lothar Herbst VP (2019) : "the condition is perfect. The stamps are general only in very small number of pieces known, therefore are they very rare. Multiple franking with special stamps, to boot with this entirely unusual double overprint. Varieties variety are extremely rare. New discovery, therefore first well known piece from an ancient collection. So far an unique. ", Michel 3.000.-