The object of this paper is to analyse which rules prohibit or otherwise restrict the possibility for discriminatory behaviour in business life.. After a sketch of the general rules which apply under constitutional law in the relation between public authorities and private individuals, this paper examines some of the main rules dealing with discrimination in business, notably in company law, financial market regulation and competition law. The final part raises the question whether general principles prohibiting discriminatory behaviour between private individuals may be found in Belgian law. We defend the point of view that this is not the case at present.