A process for producing a porous catalyst filter, the process comprising the steps of: - generating an aerosol in an aerosol reactor having a distributor section, wherein said aerosol contains aerosol droplets, and wherein said aerosol droplets contain at least one catalyst precursor salt or colloidal catalyst particles, wherein said distributor section includes a multi-hole pattern for dispersing said aerosol droplets in a desired, preferably homogeneous, pattern before said aerosol droplets enter a porous multichannel filter support; - thermally treating said aerosol droplets in a first heating zone of said aerosol reactor for decomposing said at least one catalyst precursor salt or said colloidal catalyst particles, wherein said aerosol droplets are transported into said first heating zone by a carrier gas, and wherein the temperature in said first heating zone is 100 to 500°C; and - infiltrating and depositing catalyst nanoparticles in a second or additional heating zone(s) of said aerosol reactor, wherein the temperature in said second or additional heating zone(s) is 400 to 1500°C, on said porous multichannel filter support, wherein said infiltrating includes forcing said aerosol to flow into channels of said porous multichannel filter support, and infiltrating any porous barrier/wall of said porous multichannel filter support before emerging at the outlet side of said porous multichannel filter support, wherein said depositing includes depositing said catalyst nanoparticles on the walls of said porous multichannel filter support to form a porous catalytic coating in a highly dispersed and controlled fashion, wherein said highly dispersed and controlled fashion includes said aerosol having a velocity from 0.5 to 50 cm/s along the axial direction of said porous multichannel filter support, wherein said depositing is performed on the surface of said porous multichannel filter support at a mass loading in a range of 0.5 to 100.00 g/m 2, wherein said catalyst nanoparticles have a size in the range of 50 to 2000 nm, wherein said porous multichannel filter support is a honeycomb particulate multichannel filter having a wall-flow multi-channel structure with alternatively plugged channels in which a particle-laden exhaust flow can be multichannel filtered through porous walls in which a soot deposit can grow in inlet channels, wherein said porous catalytic coating has a structure with a higher porosity than the walls of said porous multichannel filter support as can be confirmed by backscatter analysis, and wherein said catalyst nanoparticles are homogenously and finely distributed in forming said porous catalytic coating, covering said porous multichannel filter support and its pores as can be determined by SEM analysis. - generating an aerosol in an aerosol reactor having a distributor section, wherein said aerosol contains aerosol droplets, and wherein said aerosol droplets contain at least one catalyst precursor salt or colloidal catalyst particles, wherein said distributor section includes a multi-hole pattern for dispersing said aerosol droplets in a desired, preferably homogeneous, pattern before said aerosol droplets enter a porous multichannel filter support; - thermally treating said aerosol droplets in a first heating zone of said aerosol reactor for decomposing said at least one catalyst precursor salt or said colloidal catalyst particles, wherein said aerosol droplets are transported into said first heating zone by a carrier gas, and wherein the temperature in said first heating zone is 100 to 500°C; and - infiltrating and depositing catalyst nanoparticles in a second or additional heating zone(s) of said aerosol reactor, wherein the temperature in said second or additional heating zone(s) is 400 to 1500°C, on said porous multichannel filter support, wherein said infiltrating includes forcing said aerosol to flow into channels of said porous multichannel filter support, and infiltrating any porous barrier/wall of said porous multichannel filter support before emerging at the outlet side of said porous multichannel filter support, wherein said depositing includes depositing said catalyst nanoparticles on the walls of said porous multichannel filter support to form a porous catalytic coating in a highly dispersed and controlled fashion, wherein said highly dispersed and controlled fashion includes said aerosol having a velocity from 0.5 to 50 cm/s along the axial direction of said porous multichannel filter support, wherein said depositing is performed on the surface of said porous multichannel filter support at a mass loading in a range of 0.5 to 100.00 g/m 2, wherein said catalyst nanoparticles have a size in the range of 50 to 2000 nm, wherein said porous multichannel filter support is a honeycomb particulate multichannel filter having a wall-flow multi-channel structure with alternatively plugged channels in which a particle-laden exhaust flow can be multichannel filtered through porous walls in which a soot deposit can grow in inlet channels, wherein said porous catalytic coating has a structure with a higher porosity than the walls of said porous multichannel filter support as can be confirmed by backscatter analysis, and wherein said catalyst nanoparticles are homogenously and finely distributed in forming said porous catalytic coating, covering said porous multichannel filter support and its pores as can be determined by SEM analysis.