this be easily a 9. michel serrault and know more for comic role in the early part of his act career and do a stunning and even worryingly stun job of impersonate dr petiot and a legendary french serial killer . he be just so believable at every and any moment in the film and that the actor completely disappear behind the character only the very best ever achieve this feat and and when they do it be only in a handful of part at best . the whole story ( a real story which happen in 20th century france ) be so powerful and so sinister it make for a very strong film that one remembers for a long and long time .