Philippe Léotard embodies the role of the son, double on the screen of Maurice Pialat. For the role of the daughter-in-law, Pialat chose Nathalie Baye who was at that time the fiancée of Léotard.
Maurice Pialat wanted to show with that film the cancer and the agony of his own mother. He shot in Auvergne (France), close to where he spent his childhood.
For the role of the father, Maurice Pialat hesitated between Hubert Deschamps and Francis Blanche. Hubert Deschamps had to be absent quite often during the filming of 'The Mouth Agape' to shoot 'Les Gaspards' (1974) by Pierre Tchernia.
Simone Signoret revealed that Maurice Pialat wanted her for the role of the mother, but she refused. "You know," she said, "I knew the little Pialat well. He even came here to offer me the role. So what? I was surprised. - I gave him back the script and I explained to him: your script is very beautiful, Pialat, but I won't make your film. - Why not? Can you imagine me, Simone, dying of cancer on the Champs-Elysées?"
Filming the scene where a nude Monique Mélinand, playing the mother, is locked in the coffin, an embarrassing fact happened. Nathalie Baye recalled: "One day, we had to film the scene of the mother's burial. Monique Mélinand was in the coffin, we had closed it. Maurice was so absorbed by the shot, by what was happening, that he started talking to us. After a while, we heard: Knock-knock. It was awful, we had forgotten about Monique being in the coffin. Maurice was in it, he was reliving things... He wanted to go beyond what he could not do at the time of his mother's death."