Hervé Mimran did not want to make a detailed, grounded film dealing with the very real consequences of a stroke. When Christian Streiff explained to him that he would say nonsense while believing that everyone understood him, the filmmaker knew he held the key to this story. Mimran did however do a lot of research and met the stroke neurologist and the speech therapists who took care of Christian.
While inspired by the life of former Airbus and PSA Peugeot Citroen CEO Christian Streiff and his book "J'étais un Homme Pressé" ("I Was a Man in a Hurry"), the film creates a fictional narrative with fictional characters.
Hervé Mimran understood, with hindsight, that writing a film specifically for an actor is a mistake. Thus, if he had molded the main character for Fabrice Luchini only to have him turn down the role, the project would surely never succeeded. Thus with this film,the opposite happened. When the actor signed on, Mimran rewrote the character for him.