For the scene when Judge Frollo sings "Hellfire" and sees Esmeralda dancing in the fire before him, the Motion Picture Association (MPA) insisted that the Disney animators make Esmeralda's clothing more well-defined because she seemed nude.
The song "Hellfire" is considered one of the darkest songs written for a Disney film, and was nearly cut from the film.
The opening musical number, "The Bells of Notre Dame," is, according to Alan Menken, the best opening number he has ever written.
While Quasimodo is singing "Out There," the camera pans over Paris and zooms in on a street. In this scene, Belle from A Bela e a Fera (1991) is seen walking and reading her book (walks out the bottom of the screen, to the right of the well), Pumbaa from O Rei Leão (1994) is being carried on a pole by two men (carried out of the bottom of the screen, but left of the well), and another man (in a gray-blue tunic) is shaking out the Carpet from Aladdin (1992).
The opening scene, in which Clopin sings "The Bells of Notre Dame," was originally all spoken dialogue. After two revisions, it was decided that it was too dry and boring, and so was turned into a musical number.