Bones in the Wilderness — George Bellairs

The case of a missing antiques dealer brings Scotland Yard to France . . .
 
When Samuel Cheever, a shady dealer, goes to France to buy antiques and never returns, people begin to ask questions, and Superintendent Littlejohn is sent to uncover the mystery. Then, when Cheever's bones are discovered in the wilderness of the Camargue, Littlejohn finds himself having to navigate the company of the French police.
 
While working the case, Littlejohn and his partner, Sergeant Cromwell, throw themselves into la vie française with gusto: the sunshine, the food and, of course, the wine. But Cheever's trail leads to many strange places, and even stranger people, from travelers to bullfighters to cowboys -- and when one of the cowboys turns up dead and Cheever's possessions are found in his home, the investigation takes a dark turn . . .