10 C. Merkur head and 90 C. Special edition \"23. Anniversary of the triumph by Verdun\" with overprint in type I, properly franking on First Day Cover from \"Dunkerque 1.7.1940\" to Ghyvelde with on the back arrival cancel from 2.07.1940, faultless condition, expertized Beher and expertise Lothar Herbst VP (2023) : \"the condition is perfect. The stamps are only in very small number of pieces known, therefore are they very rare. \", Michel 700.-+plus