25 C. Merkur blue-green as block of four with two vertical overprinted note stamps pairs as properly franked 1 Fr. franking on cover from "Dunkerque 2.8.40" to Malo les Bains with arrival cancel from 3.8.40, cover transport traces, stamps very fine, signed Roumet as well expertise Lothar Herbst VP (2025) "the condition of the stamps is perfect. the stamps are only in very small edition from 800 pairs issued become. ", Michel 2.100.-