Sir Walter Lampson seems unconcerned when informed that his wife has been murdered. Her body was found in a stable used by horses that pull barges along canals. Another murder will follow. Who among those along this section of a canal--the café owners, bargeman, lockkeepers, skippers, and their wives--would want to kill and kill again?
The film adds a few minor things to the original novel's story (George Simenon's "The Carter of la Providence"), but the core plot is unaffected. Michel Lonsdale perfectly portrays Sir Lampson. The film's location captures the novel's description wonderfully, and this attention to detail is what makes the Bruno Cremer series so good: One doesn't read Simenon's Maigret mysteries simply for setup, epiphanous moment, and denouement. I would say the same is true of watching this series. Getting to and finding out "Who did it?" matters, yes, but only a bit. The best parts are the lingering moments in between.