A "poisson d'avril" is a joke made on April 1st. In France, children try to stick a fish picture on their friends' back. When the joke is discovered, they shout "poisson d'avril !"
"la galette des rois" the French king cake is traditionally served on January 6, a Christian holy day called Epiphany, and mostly known as the 3 wise men visit to baby Jesus. In France the tradition of serving this puff pastry and almond cream tart can be traced back to the 14th century. A small porcelain figurine (la fève) is baked inside the cake and whoever receives the little favor is then crowned king/queen for the day. So don't chew too hard in this delicious pastry, and save your teeth!!
In French, we call New Year's Eve "La Saint-Sylvestre" (pronounced "la sin(nasal) seal vay str") or "Le Réveillon du Nouvel An". Celebrated during the night of December 31st, we usually party with friends and/or family, in a more or less formal way. Let's see what French people do on New Year's Eve and learn the vocabulary.