Johnson, James H., Listening in Paris: A Cultural History, University of California Press, 1996.

Focused on the history of silence in the concert hall and opera house, this book gives a good sense of the cultural tendencies of opera goers at the time of the novel.

Perry, George, The Complete "Phantom of the Opera," Henry Holt, 1991.

Though focused on the London musical, this book is filled with information about the novel and about the Paris opera house.

Skinner, Cornelia Otis, Elegant Wits and Grand Horizontals, Houghton Mifflin, 1962.

Skinner examines the social life of uppercrust Parisian society during the Belle Époque. These are the people who would have made up the opera audience during the time that this story takes place.

Zizek, Slavoj, "Grimaces of the Real, or When the Phallus Appears," in October, Vol. 58, Fall 1991, p. 46.

This analysis examines the correlation in some folk traditions...