Author Existence Failure: Poor, poor Mary Wickes, Laverne's voice actress. This was her final film role as she died of cancer during production and had to be replaced by a stand in, although thankfully only for a few lines. Fortunately, that stand-in is sound-alike Jane Withers, who took over the role in much-maligned DTV sequel.
In the Spanish dub, Constantino Romero (Frollo), Jesús Castejón (Clopin), Salvador Aldeguer (Hugo), Carmen Contreras and Miguel Angel Jenner (The Archdeacon) did their own songs. This was one of Romero's few dubbing works where he shows his singing talents, Jesús Castejón was a stage veteran and he already performed singing for Disney as Oogie Boogie; and Jenner performed songs in previousDisney Renaissancefilms.
Celebrity Voice Actor: Demi Moore at the time became the highest paid voice actor in Hollywood, receiving $1 million for lending her voice to Esmeralda. Also Kevin Kline as Phoebus and Jason Alexander as Hugo. The sequel casts Jennifer Love Hewitt as Madellaine.
Disowned Adaptation: The descendants of Victor Hugo bashed Disney in an open letter to the Libération newspaper for their ancestor getting no mention on the advertisement posters for the film, and they harsly criticized the film itself as a vulgar commercialization of Victor Hugo's story.
Flip-Flop of God: The movie's directors have hinted that the gargoyles may all be figments of Quasimodo's imagination (a popular fan theory), but certain events in the film - namely Hugo startling Esmeralda's goat and them all taking part in the final battle - suggest they are real.
Tony Jay, who was Jewish in real life, voices the evangelical Catholic Judge Frollo.
The US stage Frollo, Patrick Page, was actually an award-winning stage magician back in his teenage years.
Mean Character, Nice Actor: In an interview for Disney Adventures that was published right around the time that the movie was released, Tony Jay made it a point to say that he was actually a very nice man in Real Life, despite continually playing villainous roles (and with Frollo being one of his darker ones).
Non-Singing Voice: Averted; with the exception of Esmeralda, every actor does their own singing. Tom Hulce, Quasimodo's voice actor, wanted to be a singer when he was younger.
Talking to Himself: During the flashback in the opening number, Jim Cummings voices about three or four characters in quick succession (one or two of the gypsy men, the boatman, and Frollo's guard). While Cummings does have an impressive vocal range, he unfortunately uses the same voice for all of these characters, making it very noticeable.
Technology Marches On: When the film was being promoted, the CGI people were touted as a huge technological advancement. They were the logical next step after the CGI stampede scene from The Lion King. Instead of using CGI to reproduce the same model making the same movements over and over again, the crowds of Hunchback were randomized, with different elements such as clothing, body types, and behaviors being mixed and matched to create these gigantic Ben-Hur crowd scenes that would, otherwise, either be much too expensive to animate, or have to be static parts of the matte. It's more noticeable now (especially if you remember watching "Behind the Scenes" featurettes which showcased the various behaviors back on the '90s Disney Channel), but at the time, especially on a first-time viewing, they were pretty impressive and evocative towards the party atmosphere in "Topsy Turvy" especially.
The Other Darrin: Jane Withers recorded Laverne's remaining lines as Mary Wickes passed away and returned to voice the character in the sequel.
In the Spanish dub, the teaser for the film had Ernesto Aura — who had a fitting voice as Constantino Romero to voice the character — voicing Frollo. The role went at the end to Constantino Romero.
Phoebus's speech rallying citizens to rebel against Frollo during the climax of the movie was originally said by Clopin, but the directors/producers felt that Phoebus needed to be more involved in the uprising.
Instead of Victor, Hugo and Laverne the gargoyles would have been named Chaney, Laughton and Quinn as homage to actors Lon Chaney, Charles Laughton and Anthony Quinn who had played the title character in previous adaptations. This idea was brought back into the German musical only named Charles, Antoine, and Loni.
The prologue was originally going to be a straightforward narration. After a couple of read-throughs, the filmmakers found it too slow and plodding. So they rewrote it as a musical number - "The Bells of Notre Dame".
A much more tragic ending was considered. Frollo would have fatally stabbed Quasimodo before being killed by Esmeralda. Phoebus would have then found them and Quasimodo's last wish would have been to ring the bells one last time.
Mandy Patinkin was originally cast as Quasimodo but left early into production because he felt the film was too different from the source material and he 'wanted to play Quasimodo for real.' He eventually did play the character in a 1997 adaptation with Salma Hayek as Esmeralda and Richard Harris as Frollo.
Cut Song: "Court of Miracles" was cut from Der Glöckner. The U.S.A. production scrapped "A Guy Like You" due to the absence of the gargoyles, but revived "Court of Miracles" (with a completely different melody and somewhat different lyrics) as a solo piece for Clopin.
Twenty year old Quasimodo is often played by men much older than he is: Forty year old Lon Chaney, forty year old Charles Laughton, forty-one year old Anthony Quinn, forty-five year old Anthony Hopkins and forty-five year old Mandy Patinkin.
Sixteen year old Esmerelda has been played by twenty-nine year old Gina Lollobrigida, twenty-eight year old Lesley-Anne Down and thirty-one year old Salma Hayek.
Fifty-nine year old Louis XI was played by the seventy-three year old Harry Davenport in the 1939 film.
A rare justification in the case of thirty-six year old Claude Frollo being played by actors older than the character due to him being Younger Than He Looks. Actors such as forty-six year old Nigel De Bruiler, sixty year old Walter Hampden, forty-eight year old Alain Cuny, forty-six year old Kenneth Haigh, forty-four year old Derek Jacobi and sixty-seven year old Richard Harris have all played the role.
Fake Nationality: In the 1939 version, the French characters are played by British and American actors. In the 1956 version, most actors are French, but Esmeralda is played by the Italian Gina Lollobrigida and Quasimodo by the Mexican American Anthony Quinn.
Reality Subtext: The 1939 version introduced a very humanist, sympathetic take on the plight of the Romani not found in previous adaptations of the story. Considering it was made by a director who had fled Nazi Germany years before during a time when the Nazi death machine was in the process of systematically slaughtering the Romani, it's safe to say it's not a coincidence. It's also worth noting it premiered at the Cannes Film Festival, which originated in opposition to the fascist presence in the Venice Film Festival (it was the only film shown that year before Germany invaded Polandthe same day).