What is New Year's Eve called in France, using the traditional name for Saint Sylvester's celebration?

In France, New Year's Eve is traditionally called Réveillon de la Saint-Sylvestre.

The name combines réveillon, a late festive meal or celebration, with Saint Sylvester's Day, which falls on 31 December in the Western Christian calendar. French speakers also commonly say le réveillon du Nouvel An, meaning the New Year's Eve celebration.

A French réveillon may involve a long dinner with special foods, champagne and social gatherings. The word réveillon is also used for the Christmas Eve meal, so the date or saint's name is important when identifying which celebration is meant.

Saint Sylvester I was bishop of Rome and is traditionally commemorated on 31 December. In modern France, the occasion is generally a secular social celebration, even though its traditional name preserves the calendar association.