The filming took place over a period of three years. As the film was self-financed, the crew shot whenever they could get funds to do it. The sequences in Germany were shot in the first place; later on, they shot in France the second part and finally they finish the shooting in Spain.
The main actors were able to develop their characters together with the writer-director. Most of the supporting cast was not able therefore to know a lot about the rest of the characters. They knew just what they strictly need for their performance.
The director mentioned that, in the end, the tone of the film become darker and darker as they film the different parts, even if it was not originally intended that way.