This presentation is given by Bruce Downs, member of the France and Colonies Philatelic Society (US).
Large French naval vessels had their own post office, and the most well-known was that on the Battleship Richelieu, which created its own identifying overprint on stamps for outgoing mail. This talk explores the reason for different stamps bearing this overprint, as well as how the overprinting of RF on the US 6c red airplane issue of the period came about for smaller ships and stations.