4, 50 Fr. postal stamp dark bluish green with inverted overprint "fortress Lorient" on Paper document with cancellation through censorship stamp "fortress Lorient 1. May 1945" and handwritten signature of the Censorship officer Schmitt, in perfect condition, only issued 100 pieces - of it only a few with inverted overprint, photo expertize Lothar autumn VP (2015) : "the condition is perfect. . . . Extremely rare. "