Google: "Purchase postcards 1900s", "postcards france", & variety of combinations.
Where on earth would one go to buy 'scandalous' postcards? Not out-and-out filth, mind you, but photos à la those of Miss Fernande. Knowledge of a bit before/after the time period would do fine, as I imagine I no one would be jarred out by the mistake, but I really haven't the slightest inkling.
Thanks in advance if you can help with this!