§ 38a Residence permit for persons who possess the status of long-term residents in other Member States of the European Union

(1) A foreigner who has the status of a long-term resident in another Member State of the European Union shall be granted a residence permit if he or she wishes to stay in the Federal territory for a period in excess of three months. …

(3) The residence title pursuant to sub-section 1 shall entitle the holder to pursue an economic activity only if the conditions stated in Section 18 (2), Sections 19, 19a, 20 or 21 are met.