The home of the Opéra national de Paris, the Palais Garnier is an opulent 2000-seat opera hall in the 9th arrondisment. It was named in deference (or recognition) of the architect, Charles Garnier. It's also the setting of the Gaston Leroux's gothic novel "The Phantom of the Opera." (I read it in English, many years ago, and the thing that has stuck with me was how funny it was, but it seems as if that's not the general feeling around the internet, so maybe I'm just strange?)
The ceiling was painted by Marc Chagall in 1964. Some people love it, others think it really stands out too much in comparison to the velvet decadence of the rest of the hall.