Children play tricks and pranks on each other, such as taping paper fishes on their backs to be silly.
The origin of this holiday is linked to the religious celebration of Lent. Lent is known as a time of fasting in Catholicism in particular and Christianity in general. To commemorate the start of Lent, the day before is called "Fat Tuesday" or Mardi Gras, a day to eat and stuff yourself with food before the 40 days of fasting begin.
The Galette des Rois cake is also celebrated around December-January because this is also the time of the religious festival of Epiphany, also known as Three King's Day, which explains the crown on top of the cake!
In some places in the world, Mardi Gras is celebrated with pancakes. In France, the tradition became crêpes, which are more commonly eaten here and are very similar to a pancake!
Fête Nationale, which takes place every July 14, is almost like our 4th of July, except France isn't celebrating independence, because they were never a colony. Instead, they celebrate the end of the Monarchy and the beginning of the Republic, where the people hold power, instead of a king. This day is celebrated with lots of fireworks and French pride! I've never been to France on this day, but there tend to be mini celebrations in New York City among other locations in the USA where there are other Francophones.
