The mystery of the lost Czanne - M. L. Longworth

Antoine and Marine are investigating both a murder and the provenance of a mysterious painting. Could it be a genuine Cezanne? Pierre, a friend from Antoine Verlaque's cigar club asks him to visit a cranky old man named Rene, who thinks he may have discovered the Cezanne. But when they arrive, Rene is dead, the painting is gone and a beautiful American art history professor is in Rene's flat. Did she kill Rene? And where is the painting? The 5th book in the popular Verlaque and Bonnet mystery series (Penguin).