Jean-Baptiste Millet / Moucadeau
In Pension Vanilos, the French Télévisions film adaptation of Agatha Christie's Hickory Dickory Dock, for the Les Petits Meurtres d'Agatha Christie TV series, Jean-Baptiste Millet is the parallel of Nigel Chapman in the original story. Jean Baptiste is portrayed by Édouard Giard.
Like Nigel, he is the son of a famous scientist, in this case Eugène Moucadeau, a Nobel Prize winner for Biology (fictional--there is no Nobel Prize for Biology, only Physiology-Medicine). Jean-Baptiste lives in the hostel "Pension Vanilos" run by Solange Vanilos. He operates a drug smuggling network in cahoots with Solange and Rose, although in this case, Solange was the mastermind and Jean-Baptiste the subordinate. Like the original Nigel, Marguerite Richard, the Patricia Lane parallel is in love with him. Louise Lambert (the Celia Austin parallel) loves him as well. In fact the cause of her death had to do with her "fetish" of rummaging among his things and finding out that he had two passports (kleptomania is not mentioned here).
Unlike Nigel, Jean-Baptiste does not have a secret family history. There is no mention of him having murdered his mother, not that her mother died unnaturally. He left home merely because he felt his father was a hard man who treated his mother badly and drove her to depression before her death. In fact, Jean-Baptiste does not try to hide his family history. When challenged by commissaire Laurence that his real name is Moucadeau, he freely volunteers that he is the famous scientist's son. He accepted that Laurence would check, merely asking that Laurence did not tell his father where he could be found.
Because of this, the reason for killing Marguerite is changed from what was in the original story. It does not have to do with her discovering who his father is but more simply because she had concluded that he had lied to her: she accepted his earlier explanation for having two passports but then later found a book with a hollowed out compartment used for smuggling. Like in the original, he killed Marguerite with a paper weight.
In this adaptation, Jean-Baptiste committed more crimes that in the original and included in his tally is the shooting of Mary Patterson and then sneaking into her hospital room to strangle her with a stethoscope, stolen from the medical student Pierre. There is no mention of how he obtained the cyanide used to poison Louise. He stabbed Solange Vanilos rather than poisoning her.