The Galette des Rois is a way for French people to celebrate the Epiphany, the arrival of the Three Wise men (Magi). Every year, on January 6th, people gather pour tirer les rois, to find the kings. The traditional galette is cut in a very specific number of slices: one slice for each person sitting at the table plus one. The extra slice is symbolic for the first poor person passing by.
The youngest person in the room goes under the table, and announces who gets the next slice. The youngest person is said to be the most innocent one and therefore fair in the distribution of the slices. Such an importance is given to the distribution because of the lucky charm, la fève, hidden in the galette.
Initially, the lucky charm was a bean but it has since evolved and was replaced at the end of the XIXth century by porcelain trinkets, and today porcelain or plastic trinkets. Today, the diversity of lucky charms is so important that people collect them. The person that gets the slice with the lucky charm becomes "the king"
for the day. French bakeries sell the Galette with a paper golden crown.
The king of the day is supposed to wear the crown as a symbol of
royalty. Even if becoming a king for one day does not have a real
influence, children (and adults!) still get excited about it because of
the fun of it. In the end, the most important part remains the gathering
and sharing of something delicious with friends and family.