A system for assisting regeneration of a particle filter in an exhaust line (3) of a motor vehicle diesel engine (1) associated with: air admission means (2); exhaust gas recycling means (4); a turbocompressor (5); a particle filter (7); a common system (8) for feeding fuel to the engine; means (16) for adding to the fuel an additive adapted to be deposited on the particle filter (7) to reduce the combustion temperature of particles trapped therein; means (20, 21, 22) for acquiring information relating to operation of the engine; and monitoring means (17) adapted to trigger a phase of regeneration of the particle filter by combustion of the particles trapped therein by triggering a phase of multiple injection of fuel. The filter (7) is impregnated with a catalyst for oxidizing hydrocarbons and CO present in the exhaust gases.