Bonne année et bonne santé is the classic French saying to wish one a Happy New Year. Literally, it is "good year and good health".
New Year's Eve is the celebration of la Saint-Sylvestre, the 33rd pope who is credited with converting the Emperor Constantine, the first Roman emperor who converted to Christianity. The feast is called le Réveillon de Saint-Sylvestre and includes champagne and foie gras. The celebratory party ranges from an intimate dinner to a grand ball, une soirée dansante.