This episode is quite enjoyable and the story relies on a plot device that I really love: a crime within an enclosed space with quite a few suspects. Lady Horbury is very glamorous, while Poirot seems quite smitten by the sir hostess Jane Grey. One of the things that haven't aged well in the series is how the detective, though asexual, almost seems to be stalking young women who show interest in case, like Jane. Or his nickname "Papa Poirot" in The Mystery of the Blue Train. From a sympathetic supporter to a creepy old guy. What makes this episode so interesting is the focus on Paris as a city, where the detective takes us on a walk along the city's most famous landmarks, like the Palais Chaillot, basilica Sacre Coeur. I love the narrative related to tennis too. Generally, I'd put this on my Christie watch list.