ट्रिविया

During the party scene, the cast held ice inside their mouths between shots to cool down their breath, so it wouldn't show on camera. It was -7 °C (19.4°F).

Ziereis actually killed around forty prisoners on his son's birthday.

The party scene is supposed to be set in Austria in spring, however it was shot in Budapest during winter. It snowed heavily the previous day and the art department had to melt the snow before the shoot.

Joan Negrié plays a character who can't speak German. He is actually the only Spanish actor in the film who can speak fluent German.

Mario Casas lost 15kg (33 lbs) to prepare for his role as Francesc Boix.