Abstract: A method is intended for desulfation of a nitric oxide trap (22) and regeneration of a particle filter (24) arranged in an exhaust line (20) for treating exhaust gas from an internal-combustion engine (10), notably a Diesel engine. The saturation rate of the trap and the clogging rate of the filter are evaluated and, as soon as one of the rates reaches a threshold value, the fuel/air ratio of the exhaust gas is increased without it reaching a fuel/air ratio of 1, then desulfation of trap (22) is performed in association with regeneration of particle filter (24).