In automotive industry, growing use of multi-material-design and the topic of modularization are the reasons for increased application of adhesive bonding after paint shop. However, surfaces of multilayer coating systems demonstrate interesting physical and chemical properties due to their complex processes during hardening. Regarding adhesion on clearcoat, paradox phenomena are observed regularly, i.e. color/basecoat dependent adhesivity. The substitution of bascoat co-solvents has been analyzed, which significantly affects the clearcoat surface properties. Depending on their reactivity and boiling ranges, co-solvents interfere with the clearcoats hardening process to different extent. The formation of dangling chains results in a lower crosslinking density of the clearcoat. The correlation between the degree of cure of the clearcoat and its adhesiveness was subsequently confirmed. A diffusion-controlled mechanism for adhesive bonding on coated surfaces is proposed. Additionally, prescreening tests to determine surface adhesion of coatings are developed. Highly crosslinked, inert paint surfaces are a challenge for one-component polyurethane adhesives. Solvent-free pretreatment methods, e.g. atmospheric-pressure plasma, in combination with polyurethane adhesives demonstrate excellent performance. The use of alternative pretreatment-free adhesive systems or (enzymatic) adhesive modifications for optimized adhesion to clearcoats is discussed as well.