The present invention relates to a method for producing a multicoat paint system on a plastics substrate, in which a basecoat film or a plurality of directly successive basecoat films are produced on a plastics substrate, a clearcoat film is produced directly on the one basecoat film or on the topmost of the plurality of basecoat films, and subsequently the one or more basecoat films and the clearcoat film are jointly cured, this method being a method wherein at least one basecoat material used for the production of the basecoat films comprises at least one aqueous polyurethane-polyurea dispersion (PD) comprising polyurethane-polyurea particles, where the polyurethane-polyurea particles present in the dispersion (PD) comprise anionic groups and/or groups which can be converted into anionic groups, and have an average particle size of 40 to 2000 nm and also a gel fraction of at least 50%.