The paper presents a case study of an ongoing implementation project in the framework of the European Union Services Directive. In the German federal state of Brandenburg, authorities are preparing a common taxonomy of professions and industries for general use and in particular for business registration. It is a measure for the creation of a point of single contact as required in the Services Directive. Existing code lists and taxonomies are used as "semantic interoperability assets" and consolidated for the new purpose with the help of the Semantic Interoperability Centre Europe SEMIC.EU). The unique contribution of the strategy chosen in the case is the combination of real-life feasibility and the instant creation of interoperability through semantic harmonization with an existing 20-language catalogue and an established classification of business activities.