The holiday season in France end on January 6th with "l'épiphanie" (the epiphany: meaning manifestation or apparition) or "La fête des rois" (the feast of kings). L'épiphanie is a Christian holiday and represents the day the Wise Men visited the baby Jesus for western Christians and for eastern Christians, it represents the day Jesus was baptized. In countries where "l'épiphanie" is not a holiday, it is observed on the second Sunday following Christmas.
In France, this day is celebrated with "La galette des rois" (the kings cake) since the Middle-ages, in honor of the wise men (called Magi Kings in French) coming to see the baby Jesus.
In the north of France, "La galette des rois" is round, golden color and represents the return of the sun after long dark winter nights. In the south of France and in Provence, it is a cake or "brioche" (soft, golden bread with an egg base) in the shape of a crown, referring to the kings. It is typically made with puff pastry cake and filled with frangipane, a cream made from sweet almonds, butter, eggs and sugar.
A small charm "the fève" is hidden in the cake. It could be made out of plastic, but is traditionally made out of porcelain. Traditionally, the cake is cut in equal parts (according to the number of guests), then the youngest of the children present goes under the table and designate how the slices should be distributed. That is to prevent cheating, since the baker of the cake would already know where the "fève" is.
The person who finds the fève is crowned king/queen for the day!
For the tradition of Epiphany in the privacy of your kitchen cut the galette in as many parts as people in the party. In one of them, insert a little ceramic toy (big enough to prevent swallowing). In the old days, they used a dried fava bean, so to this day it is still called "la fève." Everyone picks 1 piece of galette the one who discovers the toy is made the king of the day and wears the crown. He picks a queen by putting the toy in her glass and everyone raises his or her glass and applauds. Same process in reverse if a lady finds the toy. Tradition says that the next party should be at the king's expense.