50 C. Special edition \"world exhibition 1937 in Paris\" with overprint in type I, properly franked multiple franking on letter from Ghyvelde 21.7.1940 with on the back arrival stamp from 22.07.1940, faultless condition, expertise Lothar Herbst VP (2019) : \"the condition is perfect. The stamps are only in very small number of pieces known, therefore are they very rare. \", Michel 900.-