The more I read this novel, the more it felt like an episode of the 1970s TV detective series 'Columbo', albeit with a Mediterranean flavor.
Inspector Maigret is prompted to leave Paris to take up the case of a small-time crook, who was murdered after boasting aloud at a crowded public establishment of his "friendship" with Maigret. So, in company with a French-speaking Scotland Yard detective (named Pike, who was visiting Maigret's jurisdiction from the UK to observe his counterpart's investigative methods), Maigret travels by train to a small Mediterranean island off the coast of Southern France, where the murder had taken place.
There are a number of suspects: a rich, old Englishwoman who lives on a yacht berthed in the harbor; her companion Philippe, a rather vain sort with an exaggerated sense of self-importance; Charlot, a conceited loudmouth who fancies himself a know-it-all; a young Dutch nihilist and painter not much given to talking; a retired British major living the expatriate life; Monsieur Emile, a rather mousy man who lives with a controlling mother; and Ginette, an aging prostitute and an old acquaintance of Maigret whom he had helped years ago escape from a dangerous relationship with the same thief, whose murder Maigret is now investigating.
The story unfolds in an almost leisurely fashion as if in keeping with the languid atmosphere of the island. This is a book best enjoyed in one's quiet hours with a drink (whichever one suits your tastes) or in bed with the overhead lamp alit.