Well, it's hardly the Hound of the Baskervilles, but the eponymous yellow dog of the story is considered a harbinger of ill fortune by the Breton townsfolk of Concarneau: a relative of the folkloric hellhounds of Britanno-Celtic legend.
Maigret is on one of his many secondments to Brittany, and also in one of his most quixotic moods, presenting himself as bumbling, unconcerned and obtuse, all the while unerringly closing in on his suspects 4⭐