Here are some more French Poisson d'Avril or April Fish cards. Yesterday's cards all featured lovely women; today's all feature children. As the first card explains, these children are continuing a long tradition of offering fish and flowers for the first of April.
A typical card might have a message on the back that says, "Guess who sent you this." The cards are often joking and romantic at the same time.
Here's the back of the first card, sent on April 1, 1904.