A rich man, honest, hypochondriac, and only moderately happy in his home life, disappears after having asked his chauffeur to drop him off in the middle of Paris. An unplanned, unannounced vacation? An escape into another life? Or foul play? Commissaire Dax considers it his worst nightmare to have to deal with a case involving a missing person who's a social acquaintance of the Chief of Police. But with the help of Felix, his anglophile young assistant, and Georges Alder, expert in shadowing suspects, he manages to construct an image of the missing man's last day. Then dead bodies and missing gems start turning up, and it becomes clear that something is very wrong indeed.
As with many mysteries set in France written by English author, the book abounds in French idioms, not always idiomatically deployed. This is a police procedural - we hear nothing about Commissaire Dax' private life - it's all about the investigation. An enjoyable, not too demanding quick read.