Stamped

If you've been looking at the backs of these cards, you may have noticed something curious. Despite their postcard format, very very few appear to have been mailed. Most are written across the whole back, no room for an address. However, most of the messages imply they were sent from one place to another, rather than given in person. It seems most of the time they were put into envelopes like greeting cards, and, indeed, on some you can see a faint imprint where the postmark was stamped down on the envelope. 

Why these were usually put in envelopes, I'm not entirely sure. It may have been in part because the messages are often quite personal, and no one wants their love letters read. Another factor, however, is perhaps the fact that in 1920s France, stamps had to be put on the front of postcards (exactly when this requirement started and ended I'm not sure, but it was the case for at least most of the span of these cards). I suspect often people simply just didn't want to mess up the pictures. 

Two of the rare instances with the stamp on front:

Another card sent for St. Catherine's Day.