USA Aug. 5th 1940 air mail cover to France. By German regulations on postal services in Occupied France, incoming mail from all sources was exchanged at the Censorship Office in Paris & only 300 letters per day were accepted. This letter was flown to Portugal & then went by surface mail to Paris. It was opened by a German censor& on the reverse bears a hand stamp with the code "X" of the Paris office. Samur was in the occupied zone & the letter was not forwarded. Before return from France, the 3-line explanatory mark was added. The large "RETURN TO SENDER / SERVICE SUSPENDED" was applied in the USA.