Christmas travels

I'm spending Christmas in Europe, like some sort of peasant orphan globetrotter. Paris, Zurich and Vienna, with a forecast of a cold snap all through December and temperatures well below zero at times. Hot chocolate in a left-bank Art Deco cafe? Yes. All-day shoe and brooch hunts through the Marais? Yes. Gluhwein and carols in St Stephen's Square? Lying in the bath with champagne while snow falls outside the window? Also yes.