A configuration for purification of an exhaust gas flow of an internal combustion engine includes at least one exhaust gas line having an element for exhaust gas purification with a first end face and a second end face. The exhaust gas flows through the element from the first end face to the second end face. An adding device is provided downstream of the element for adding a reactant to the exhaust gas flow. The adding device is positioned at a distance of no more than 30 mm from the second end face of the element in such a way that at least part of the added reactant strikes the second end face of the element. A method for adding a reactant into an exhaust line during the operation of an internal combustion engine is also provided.