The good:
Set in Paris.
The basic plot idea is interesting.
It was written by Laurie R. King and I thoroughly enjoyed The Beekeepers Apprentice.
The bad:
Long on irrelevant details. Every bar that the protagonist visits in search of clues is detailed.
Scenes jumped around from here to there.
A couple of times I noticed he/she were mixed up.
Details that were unrealistic: police leaving lock-picking tools and case notes in Stuyvesant's suit after he was arrested.
I was unsympathetic to the protagonist. Harris Stuyvesant, former FBI agent, sounded more like a hokey tourist than a private investigator.
The secondary characters were unbelievable.
How does Stuyvesant determine if photographs of possible victims are real? Send them to be looked at by a shell-shocked war veteran who is good at reading people.