Air Union Charged Cover, 1939 re-used on the Mermoz Route via Air France, front

The big diagonal Stamp in the Middle says "LETTRE CHARGEE", meaning the Cover was for mailing Values (Notes, Shares, Securities, Order or other precious Content).

That's why the Stamping's almost 10 Times the standard One !

 

Papers, Inks and greasy Ink

 

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