I picked up this book at Shakespeare and Co in Paris. I know, it's not the real Shakespeare and Co run by Sylvia Beach, but it's a reasonable facsimile and there are lots of lovely books there. Wilhelm found a history of France that he is now enjoying.
Murder in the Latin Quarter (2009) appealed to me because of the photo on the cover. That could be the street where we were staying. It really looks just like that at night in the neighborhood behind the Quai de Montebello.
And of course the chance to read a book that took place in the streets that we had been walking in recent days was not to be passed up.
The first book in Cara Black's Aimee Leduc series is Murder in the Marais, published in 1998.