The invention concerns a system for assisting regeneration of a particulate filter (6) arranged in an exhaust line (3) of a diesel engine (1) associated with a oxidizing catalyst (7), the engine (1) being equipped with feeding means (8) for injecting into the cylinders thereof at least one post-injection. Said system comprises means (17) for controlling the feeding means (8) in accordance with a strategy for regenerating the filter (6) wherein the feeding means (8) are switched between a first operating mode with post-injection for priming the catalyst (7) and a second operating mode with post-injection for producing an exothermic reaction by the primed catalyst (7). Said system comprises a temperature sensor (18) arranged in the exhaust line (3) upstream of the catalyst (7), and the control means (8) are capable of switching the feeding means (8) between the first and second operating modes based on said sensed temperature.