The invention concerns a device for reducing the amount of soot particles discharged from the exhaust gas system of an internal combustion engine. Owing to the addition of an additive to the fuel, the ignition temperature of the soot particles during afterburning is reduced to between approximately 300 and 350.degree. C., so dropping far below the normal operating temperature of the unit. Consequently the regeneration process of the filter in the unit starts comparatively early. An essential component of the present invention is the so-called deep-bed filter which is composted of a plurality of rolled-up tubes of special ceramic thread and a heat-resistant resilient steel wire. The special production method and special construction of the ceramic stack according to the invention guarantee a satisfactory useful life of the soot filter which withstands vibrations and mechanical stresses.