Credit to Wikipedia for the information in this post about April Fool’s Day in Paris. In France as in Belgium and Italy, children and adults traditionally tack paper fishes on each other’s back as a trick and shout “April fish!” (in French. “poisson d’avril!”). Such fish feature prominently on many late 19th to early 20th century French April Fools’ Day postcards. Try this on your boss next April first to see if he/she has a sense of humor.