For the scene in which Quasimodo is whipped, Charles Laughton instructed an assistant director to twist his ankle outside of camera range so he would really be in pain. Even through the heavy hump and rubber body suit, he felt every lash and often came home badly bruised. Before the 16th take, director William Dieterle whispered to him, "Now, Charles, listen to me. Let's do it one more time, but this time I want you . . . I want you to suffer." According to Laughton's wife, Elsa Lanchester, the actor never forgave him for that.
The only movie screened at the very first Cannes Film Festival (the remainder of the festival was cancelled after Adolf Hitler invaded Poland on 1 September 1939).
The scene in which Quasimodo rings the cathedral bells for Esmeralda was shot the day World War II began in Europe. The director and star were so overwhelmed, the scene took on a new meaning, with Charles Laughton ringing the bells frantically and William Dieterle forgetting to yell "cut." Finally, the actor just stopped ringing when he became too tired to continue. Later, Laughton said, "I couldn't think of Esmeralda in that scene at all. I could only think of the poor people out there, going in to fight that bloody, bloody war! To arouse the world, to stop that terrible butchery! Awake! Awake! That's what I felt when I was ringing the bells!"
Well aware of the war raging in Europe, Charles Laughton chose a lull in the day's shooting to recite, in full Quasimodo costume, Abraham Lincoln's Gettysburg Address, as he had done in "Ruggles of Red Gap (1935)." As in the previous film, it stunned the cast and crew for the rest of the shooting day.