Since it's not a famous work, I started reading it without high expectations, but it's quite good. Inspector Giraud appears as a rival detective. Well, he's a complete pushover, but the exchanges between Poirot and Giraud are interesting.
The exchanges between Poirot and Hastings are also good. I also like the scene where Hastings seems to side with Inspector Giraud instead of Poirot. As usual, Poirot focuses on something incomprehensible, but later it turns out to be important. I also like the kindness of Poirot trying to guide Hastings, who can't keep up with the understanding. After the result is revealed, you think the rest is just a matter of cleaning up, but then there's another twist, which was quite surprising. I was horrified when I found out who the real culprit was. There are also scenes like "Poirot vs. Hastings," so I liked the unexpected aspects. It's a good old-fashioned, culprit guessing quiz type novel. I read it without any expectations, but I thought, "It's more interesting than I thought. It's quite a gem."