The first two and a half weeks of filming took place in Germany, followed by three days in France and seven weeks of filming in Sertã, Portugal. The director said in an interview that he had to speak English and French with some actors, and Portuguese with some crew members, which was exhausting and mentally draining.
During the casting process, they shortlisted eight actors and auditioned them in Paris. Among them was Hugo Fernandes. When Hugo and other actor auditioned in Portugal, both delivered great performances, but Hugo stood out. Even in Paris, after the initial auditions, there was a feeling that Hugo might be the one. However, the team wanted to be thorough and continued considering others, only to confirm that Hugo was perfect. His five scenes were exceptional. Though Hugo had acted in a few films before, he only takes roles he's genuinely interested in, as he is primarily focused on his fine arts studies and doesn't see acting as a definitive career path. The casting team was moved by Hugo's performance, because he embodied everything they had envisioned. It felt as if the script, written for an almost imaginary actor, had always been meant for Hugo Fernandes.
Hugo Fernandes fully immersed himself in a character vastly different from his own personality, to the point of experiencing physical manifestations of stress, including an acne breakout. He later reflected that his subconscious seemed to generate immense pressure throughout the process. Because the film was shot almost entirely in chronological order, the character's transformation is clearly visible on screen. The shoot began in Cologne, which served as Paris in the story, with only one scene-the police interrogation in Paris-being filmed out of sequence as the very last scene. By the end of production, Hugo was completely exhausted. He worked tirelessly from Monday to Saturday without a stable base, staying in Sertã, a place he had never been before, which mirrored his character's disoriented state of mind. The isolation and unfamiliarity of Sertã, far from his family, added to the emotional intensity of his performance. The final two scenes were filmed in Lisbon, but by that point, Hugo was struggling with sleepless nights and severe stomach pains. His dedication to the role was so profound that his subconscious fully committed, pushing him to embody the character in every aspect.