Probably closer to 3.5 stars, but of course, Goodreads doesn't allow half-star ratings.
Completely by chance, this is the second straight story I'm reading (after Andrew Cartmel's Ashram Assassin) that is the 2nd book in a series where I've not read the first one (in my defense, I just wander amidst the books until I find something intriguing) - however, with that said, this for the most part is pretty accessible as a standalone. Sure, there's some references to a previous mystery and what appears to be a few recurrent characters, but most of the seemingly important stuff from the previous story is rehashed for us anyways, so you don't really feel too lost (other than not knowing why exactly her previous go-around ended up with so many dead people).
A cozy little mystery (as cozy as murders can be) taking place in 1924 Paris - and without the sort of high-stakes, governmental/corporational conspiracy sort of angle that so frequently seems to intrude into stories (it can be fun, but it is also overdone) - we follow our lead character Zoe in what starts as a quick trip to a pop-up market to replace an accidentally broken clock and quickly turns into a murder investigation of sorts. Of sorts, I say, because she's not really a detective - an amateur, maybe, or maybe even nothing more than a step-up from armchair detective (because she does get up and go around and put herself in danger). I feel like 'amateur' is overcalling it, even if this is in fact her second such mystery, because it is more out of curiosity and "I sorta knew her" (them, once the second murder takes place) and less out of wont to be a detective (which is probably ideal, because aside from her apparent enjoyment in reading Poirot novels, she's not exactly got the mind of a detective).
Thrown in amidst the murders is a story about numerous missing paintings - it is actually the discovery of one of these missing paintings that actually gets Zoe on the move and has her discover the initial murder in the first place. From there, the story goes multiple ways - she tries to find more missing paintings, she tries to figure out who would murder the clock seller, she navigates the backdrop (1924 Paris, in the midst of hosting the Olympics and still reeling from the recent war and with the very prevalent anti-German feelings harbored by many), she tries to help out a neighbor in a very difficult-to-escape situation, and she recalls life growing up in the very racist south of America (with particular flashbacks to one person/sequence/event that truly changed her life). The intersection between these stories aside from involving Zoe, are fairly minimal. There's also a couple odd chapters given to us from the point of view of another character, which I'm assuming is setting up some sort of longer story arc that'll be dealt with in the 3rd book (or later) of this series, because otherwise it's just very out of place and unnecessary here, and it doesn't add anything (beyond word count).
Part of being a cozy with a hesitant "just helping out" investigator is that she is, obviously, not a competent detective. So she makes a bunch of mistakes, misses some pretty obvious seeming things, and of course, in 'very common in stories' form, upon figuring things out, decides to do stuff on her own without involving anyone else or letting anyone know. (Yes, in the story, this is explained away by her ending up on the phone with a very unhelpful cop, but like, then tell someone else? You've spent the whole story not being afraid of involving others, and now, at the worst time, you go alone?)
This mostly becomes a bit much after the second murder. After the first one, it makes sense that she's got a very broad list of suspects - but after the second one, I think it becomes very obvious who the primary suspect should be. The reason is still unknown, of course, but the 'who' is pretty obvious. And as the story unfolds, the 'why' also shows itself pretty clearly - and she just completely ignores it/misses it. Repeatedly. The story does do a decent job of trying to expand the pool of suspects with a simple thought of "maybe she saw something" (which, fun enough, ends up being the actual reason for death), but the stretches Zoe has to make to explain why other folks may be suspects seem a bit farfetched when she keeps missing the obvious suspect. Additionally, the whole 'missing painting' backdrop adds a few characters and scenes but, aside from a couple of unsatisfactory attempts to further investigate this previous 'crime' (which is pretty easily explained almost immediately) and one particularly unsavory character, it doesn't really add much to the story. Misdirection, I guess, but I wasn't a huge fan of how much it strayed off the path.
While there were many tangential stories mixed in that lead you down multiple weird, parallel alleys that never fully intersected (thus my description of them as parallel alleys), the story itself flowed pretty well. Zoe has a pretty tragic backstory that slowly unfolds to us and makes her seem a bit more sympathetic, especially when countered with the present-day Zoe who is sticking her nose into many places it doesn't belong (which is even more inexplicable given the apparent story of the 1st novel, which ended with many deaths). Sure it all ends well and she's able to help a bunch of people, but she's also not exactly blameless herself (in multiple ways). We do get to see 1924 Paris (Olympics, post-war, all of it) as a well-written, decently-explored backdrop that is well used to enhance the story. ... Again, I understand she's not even an amateur detective so this may not fully be her cup of tea, but, like - the answer was right there all along!