Awful show, a bad take on "Death in Paradise" combined with "Lovejoy". I can't ever imagine a police chief recruiting someone (especially someone not French) to assist in crimes and murders and let them go off on their own and be detectives.
The characters are lifted straight from the show "Benidorm", the plots are ludicrous and there is no way an amateur antiques buyer would ever figure out some of the crimes - especially the missing religious relic episode.