The posters in the Institute are adaptations of historical posters of the real Fassman, modified to replace Fassman's face with Juanjo Puigcorbé's.
The movie was filmed in Catalan language. For the Spanish language version, the captions in typewriter font sometimes appearing superimposed on the screen are translated (When Fassman reads the first anonymous letter, the word "mentider", meaning liar, appears next to his face; it's translated to "mentiroso" in the Spanish version; in both cases, when the letter is seen, the word written was in Spanish). For the Spanish version, some character names were also translated to the Spanish version of their Catalan names (e.g. Jordi becomes Jorge; Mercè becomes Mercedes; Rafel becomes Rafael)