Which landmark served as a setting for "The Phantom of the Opera"?

The Palais Garnier, historically known as the Opera de Paris, or simply the Opera, is a 2,200-seat opera house that is also a major landmark in the French capital. For locals, the ornate opera and ballet theater is as much a part of the city's cultural fabric as Notre Dame, the Louvre, or the Eiffel Tower. For others, it became known as the setting for "The Phantom of the Opera."

Source: CGTN