25 C. Merkur blue-green as block of four with two vertical overprinted note stamps pairs as properly franked 1 Fr. Franking on letter from "Dunkerque 2.8.40" to Malo les Bains with arrival stamp from 3.8.40, faultless condition, signed Dartyre and red owner sign as well photo expertize Lothar Herbst VP (2015) : "the condition is perfect. The stamps are only in very small edition from 800 pairs issued become. There only a small proportion of it have been preserved is, are such stamps very rare. Different overprint position (K) "falling) top down running) is as special feature to mention. ", Michel 2.100.-