40 C. 60 C. special issue "Parisian Postal service museum" with overprint in type II, in perfect condition mint never hinged - with reverse strike of the Postmark "Coudekerque business" and signatur of the post office leader as authenticity marking, only issued 80 - 100 pairs - very rare, signed Pickenpack amongst other things and certificate with photograph autumn VP (2014) : "the condition is perfect. ", Michel 1. 700.-