This system for helping to regenerate a catalyzed particulate filter arranged in a motor vehicle diesel engine exhaust line, said filter (4) being positioned downstream of an oxidation catalyzt (3) on the output side of the engine (1), is characterized in that it has a gas bypass circuit (5) parallel to the terminals of the catalyzer (3) and fitted with means (6) for controlling the circulation of gases therein and in the catalyzer, in order, at the point when the regeneration of the particulate filter (4) is triggered, to divert a proportion of the gases laden with unburned hydrocarbons into the particulate filter (4) without passing via the catalyzer (3), so as to speed up the regeneration of the particulate filter.