Salvelinus alpinus. Omble chevalier (often just ‘omble’) or Arctic char is a firm fleshed fish that lives in the lakes of northern Europe and Canada, and in Alpine lakes (the main ones in France are Lakes Annecy, Léman and du Bourget).
It tastes like a delicate version of salmon, and is frequently farmed.
Image by Jim Gaither, U.S. Fish and Wildlife Service