In Le Crime est notre affaire the 2008 French adaptation by Pascal Thomas of 4.50 from Paddington, Frédéric Charpentier is the youngest son of Roderick Charpentier. He is the father of Alexie Charpentier, the Alexander Eastley parallel. This makes Frédéric the parallel of Bryan Eastley in the original novel except that Frédéric is Roderick's son and not son-in-law. He is portrayed by Melvil Poupaud.
Unlike Eastley, Frédéric is not a former fighter pilot nor does he have any remarkable achievements in the past. According to his daughter Alexie, the rest of the family consider him a failure and call him "Frédéric the layabout". Indeed, he tells Prudence at one point that he doesn't have an alibi for the time the dead woman found on the chateau grounds is believed to have died. When asked to try to remember, he says only that he doesn't like looking back into the past, there is nothing worthwhile to remember.
It is not clear what exactly Frédéric does for a living. Alexie tells Prudence that she does not mind if the rest of the family look down on him. For her, it is enough that her father is a good guitarist. He is also devoted to his late wife. He likes Prudence because she reminds him of his wife. Like Prudence, she was always cheerful and spread joy everywhere. He admired how she stood up to his father. She was not intimidated and actually got on well with the old man. Frédéric puts his guitar skills to good use. At one point he tries to teach Prudence the guitar, much to the chagrin of Bélisaire.