No one knows the exact origin of April Fool’s Day, but France has its own claim. Up until the middle of the 16th century, the New Year was celebrated in late March in Europe, ending on April 1. When Charles IX announced that the holiday would move to January 1, some people protested and continued with the spring celebration.
Traditionally, the spring celebration had involved public gatherings and the exchange of gifts, often fish. When the holiday moved to January, the people who had made the switch mocked people who still celebrated on April 1 by attaching a small fish to the back of their clothes. When a victim finally discovered the fish on their back, someone would say “poisson d’Avril!”
The tradition continues to this day but typically in the form of a paper fish. Wherever you are in the world today, watch your back!