Method for treatment of an exhaust stream , which results from a combustion in a combustion engine , passes through an exhaust treatment system and comprises nitrogen oxides NO x , wherein said nitrogen oxides NOx comprise nitrogen monoxide NO and nitrogen dioxide NO 2 ; comprising - a first oxidation of compounds comprising one or more of nitrogen, carbon and hydrogen in said exhaust stream , wherein said first oxidation is carried out by a first oxidation catalyst , arranged in said exhaust treatment system ; - a determination of a value (NO 2_1 /NO x_1 ) det for a ratio between a first amount of nitrogen dioxide NO 2_1 and a first amount of nitrogen oxides NO x_1 leaving said first oxidation catalyst ; - an active control of at least one parameter related to said combustion engine based on said determined value (NO 2_1 /NO x_1 ) det for said ratio; - a first supply of a first additive into said exhaust, stream with the use of a first dosage device , arranged downstream of said first oxidation catalyst ; - a first reduction of said first amount of nitrogen oxides NOx via a catalytic reaction in a catalytic filter , arranged downstream of said first dosage device , wherein said catalytic filter consists of a particulate filter with an at least partly catalytic coating with reduction characteristics, which is arranged for catching and oxidising of soot particles, and to carry out said first reduction of said first amount of nitrogen oxides NO x_1 , wherein said catalytic reaction uses said first additive, and - wherein said active control impacts on said ratio depending on whether to achieve an effective soot oxidation in the catalytic filter or to achieve an effective reduction of nitrogen oxides in the catalytic filter. - a first oxidation of compounds comprising one or more of nitrogen, carbon and hydrogen in said exhaust stream , wherein said first oxidation is carried out by a first oxidation catalyst , arranged in said exhaust treatment system ; - a determination of a value (NO 2_1 /NO x_1 ) det for a ratio between a first amount of nitrogen dioxide NO 2_1 and a first amount of nitrogen oxides NO x_1 leaving said first oxidation catalyst ; - an active control of at least one parameter related to said combustion engine based on said determined value (NO 2_1 /NO x_1 ) det for said ratio; - a first supply of a first additive into said exhaust, stream with the use of a first dosage device , arranged downstream of said first oxidation catalyst ; - a first reduction of said first amount of nitrogen oxides NOx via a catalytic reaction in a catalytic filter , arranged downstream of said first dosage device , wherein said catalytic filter consists of a particulate filter with an at least partly catalytic coating with reduction characteristics, which is arranged for catching and oxidising of soot particles, and to carry out said first reduction of said first amount of nitrogen oxides NO x_1 , wherein said catalytic reaction uses said first additive, and - wherein said active control impacts on said ratio depending on whether to achieve an effective soot oxidation in the catalytic filter or to achieve an effective reduction of nitrogen oxides in the catalytic filter. <EOS>