Amazingly well-realized murder mystery in an imagined "pair" of cities. Great noir atmosphere. Evokes living behind the Iron Curtain, the many-layered history of Eastern Europe's cities (many spent several hundred years as Ottoman towns before being recaptured and remade into Austrian/Hungarian/Serbian/etc ones), and the social strains from gentrification, all in one.
The only ding I have is that it's told in the first person, but the narrator is sort of transparent. That is, they didn't seem to have a strong POV to me, so it reads more like third-person than anything else.
Still, it's well done, with a solution (and an ending) that I did not see coming, but felt natural and, really, perfectly encapsulates the themes of the book.