Contrary to the others films she did in France before this one and where she was dubbed (by Claire Guibert), this was the first time Gina Lollobrigida spoke her lines in French (with a strong Italian accent).
The scene of Quasimodo's coronation was shot twice for each version of the film. For the original French-language version, he is crowned 'Pope of Fools', as in the novel, and wears a mock Papal tiara. For the English-language version, he is crowned 'King of Fools', and wears a royal crown. This was because the American Hays Code forbade mocking of the clergy.
The original French-language version contains two scenes cut from the English-language version. In the first, after the stabbing of Phoebus, we see Pierre Gringoire, surrounded by his friends from the Cour des Miracles, worrying about Esméralda's disappearance. In the second, after Esméralda's rescue, we see Claude, back at the scene of the crime at La Falourdel's, breaking down on the floor, and talking about guilt and the state of his soul. This then leads into his return to the cathedral.
The notorious torture scene, where Esmeralda is questioned in the "boot," is rather inaccurate. The prop used is an ornate golden boot that bears little resemblance to any historic torture devices. The type of boot referred to in the original novel would look much more like a simple vise that squeezed the bare foot between two iron plates, likely studded with teeth.