This is a turquoise-green colour morph of Carabus nemoralis. Carabus nemoralis is a species with relatively few colour variations in the core of it's West European distribution. Most individuals have brownish- coppery elytra and a blue to purple coloured pronotum (thoracic shield). In the south and espcially the subspecies 'pascuorum', often shows very nice colour variations. Close to the Gourg de Lantre, in the Aude, I found a vivid turquoise-green individual and another one with a golden green colour.