In February 1897, 800 copies of MiNr. 1-6 were printed specifically for the Universal Postal Union office in Bern, Switzerland. Of the 800 sets, 760 were distributed to member countries, 5 to each member nation. The remainder were used by the Reich Post Office for exchange with a Mr. Antoine in Berlin.
These issues differ slightly from the postally-issued MiNr. 1-6. They feature a heavier overprint and the 3 Pf. is a different shade of medium brown (originally Deutsches Reich MiNr. 45 b).