The Paris Apartment by Lucy Foley

Running away from trouble in the UK, Jess arrives in Paris to hole up for a while with her brother Ben, who has half-heartedly invited her (or rather acceded to her inviting herself). But when she gets to his flat in an upmarket apartment block, Ben is nowhere to be found and a patch of bleached floor testifies to something sinister. Jess has nowhere else to go. She stays and tries to understand what happened.
The neighbours aren’t friendly or forthcoming with any information about Ben. It seems like they close ranks or simply don’t know; or perhaps it is their famous French discretion. Each of them harbours their own version of Ben and what their relationships with him were like. None of them were straightforward. Their memories are coloured with emotions, frayed, and there are huge gaps as information is withdrawn from the reader until the very end. None of the characters are likeable or trustworthy and that includes Ben as seen through their eyes. You can’t tell whether he was a victim or a perpetrator. The suspense is maintained right to the final chapters.
There are hard-hitting themes in this tense psychological thriller: alcoholism, sexual exploitation, modern slavery, drugs, societal inequalities, police corruption and the corruptive effect of wealth on morality and family dynamics etc etc etc.
Although the ending was inevitable and therefore expected, the nuance of it and the few final twists make it worth reading to the last page while remembering to breathe.
My only tiny issue was with the slowness of retrospection when each character speaks for themselves – there is a lot of internal monologue, telling rather than showing, and repeated explanations. That adds up to the over 400 pages of this book, which if some of that was left to the reader to work out for themselves would make this book much tighter and faster-paced.