From the description on Amazon:
The story begins in Paris at the famous First Impressionist Exhibit on April 15, 1874. But later that night, when the body of a countess is found in the Rue Cassette, Serafina is sent by the slain woman's wealthy father to investigate the brutal murder. Her budget bountiful, Serafina and her entourage stay at the plush Hôtel du Louvre, dine at Véfour and La Maison Dorée, interview friends of the deceased, have a midnight snack at Les Halles, visit with Berthe Morisot, Cézanne, Les Mardistes and other artists, and lock horns with the French police. As the plot twists, Serafina and her friends find themselves in the savage grip of a mind gone feral.
This is the third book in the series (or fourth, counting a novella, that only existed in e book form).
As I have mentioned before, I really like this series of mysteries, set in 1860's Italy (Sicily). One thing I really like is that the main characters are so nice and interesting.
Just like the other books in the series, this is a well written mystery, in a fascinating setting, with a number of well developed characters.