Maigret gets a busman's holiday to Normandy, and we learn a little about his humble origins in the process, which perhaps explains his affinity with the down-at-heel and the hard-done-by.
That said, the rather well-to-do old lady of the title, who asks Maigret to investigate the murder of her maid, charms him with her eccentricities. Simenon slowly unpeels the psychology of his characters, and Maigret's attitude towards them turns accordingly.