INTER-ALLIED COMMISSION - INTERIOR DEPARTMENT, postage-free letter from French department member, carried by authority courier service as diplomatic mail/bag (manuscript valise diplomatique) to Paris, later redirected there, violet double-circle official seal COMMISSION INTERALLIEE DE GOUVERNEMENT ET DE LA PLEBISCITE DE HAUTE-SILESIIE - DEPARTEMENT DE INTERIEUR (OS handbook no. I.1.b.), elliptical lilac official seal COMMISSION INTERALLIEE DE GOUVERNEMENT ET DE LA PLEBISCITE DE HAUTE-SILESIE - SERVICE DU COURIER - 25 AOUT 1920, rare, envelope vertically folded through centre