An interesting thriller

Interesting book with a detective story about a historical background of the city of Lyon. It is true that this book may seem long in description, but personally knowing Lyon, I could identify the different places mentioned and I found it very informative.
The plot is very well fitted with Gaidon of life. It is not in the discovery of the murderer but rather in the resolution of the investigation with the various indices that are available to the police.
The pace is fast enough that we want to know the end. The characters are common, they have nothing original, but the intriguing era brings about a loss of reference for the reader that we are contemporary.
I loved ...