A process for the production of a multi-layer coating includes: 1) applying a 10-30[mu]m coating layer from an aqueous pigmented coating composition A onto a substrate provided with an EDC primer; 2) applying a 10-25[mu]m base coating layer from an aqueous coating composition B overlying the coating layer; 3) applying a 30-50[mu]m transparent coating layer onto the base coating layer; and 4) jointly bake-curing the three coating layers. The coating compositions A and B are different from each other. The coating composition A comprises (i) binder solids, (ii) free polyisocyanate, (iii) a pigment content free of special effect pigments and comprising carbon black pigment and/or titanium dioxide pigment, and (iv) a talcum filler. Wt.% is based on solid serving as a reference and based on 100wt.% being the total amount. The binder solids are formed by a 10-50wt.% aqueous (methyl) acrylic copolymer emulsion binder, a 50-90wt.% aqueous polyurethane binder and a 0-30wt.% one or more other binders. Or, a resin solid being taken as a reference, a 2-3.5wt.% talcum filler is contained, and the free polyisocyanate is a combination of one or more kinds of aqueous polyisocyanate and one or more kinds of normal polyisocyanate. Or, the coating composition B contains a 10-50wt.% aqueous (methyl) acrylic copolymer emulsion binder, a 5-45wt.% aqueous polyurethane binder, 15-50wt.% melamine formaldehyde condensation resin, and a resin solid composition formed by one or more other binders, wherein wt.% is calculated by taking the solid as a reference and 100wt.% as the total amount.