Cancer pagurus. Tourteau is the crab that you usually see in the fishmongers, and common in the Atlantic and North Sea. They are often sold live, like lobsters, with the powerful claws strapped in a band, although fishermen often cut the muscle that allows them to close.
Many people buy just the claws, the pinces, boiled and ready to eat, especially around the Christmas holidays when seafood platters are a thing.
Also known as crabe dormeur, crab epoupard, crabe poupart, crabe-de-lune, poing-clos, clos-poing, or ouvet.
Image by Hans Hillewaert