Palais Garnier
8 Rue Scribe, Place de l'Opera, 9th
Though it's arguably most famous for being the backdrop to Gaston Leroux's The Phantom of the Opera, its real acclaim comes from the fact that it's a stunningly opulent Second Empire masterpiece. While in its first life it was home to the Paris Opera, it now hosts the Ballet. It's absolutely worth making a night of it if only to see the Grand Foyer.
