Abstract: An exhaust system of a multi-cylinder internal-combustion engine has at least one system part in which the internal-combustion engine exhaust gases or portions thereof are first guided through at least two partial pipe trains apportioned to cylinder groups, in which partial pipe trains, one starting catalyst respectively is inserted and which combine to form a joint main pipe in which a main catalyst is inserted, at least one lambda probe being arranged in front of and one lambda probe being arranged behind the catalysts. In front of each starting catalyst, a lambda probe is arranged and an additional lambda probe is arranged in at least one partial pipe train behind the starting catalyst.