A butcher, a man with a whip, and a jolly bishop walk into a bar. This is not, in fact, the opening line of a twisted joke—it’s preparation for the biggest day of the year in Nancy, an elegant city in France’s Lorraine region. St. Nicholas Day is celebrated across many European countries on December 6 or the weekend following it. Each evening in Nancy from late November till early January, a lights display projects a story onto the opulent façade of the Hôtel de Ville. The expectant crowd watches…