An exhaust gas system for converting harmful substances of an exhaust gas of a mobile internal combustion engine includes at least one reducing agent feed, a catalytic converter, a filter element and an exhaust pipe. The reducing agent feed opens into the exhaust pipe upstream of the filter element, while the catalytic converter is disposed downstream of the filter element, as seen in exhaust gas flow direction. Additional components, such as a mixer, a pre-catalytic converter and a heating element, etc. used for purifying exhaust gas, may also be advantageously integrated into the system.