Yes, you may accept external students from other institutes/departments/universities or exchange students in your course, provided there are still places available in your course. However, priority is always given to students enrolled in the degree program in which your course is offered. 

External participants cannot be registered in Campus Management. At the end of the course, you will provide them with a signed certificate of achievement to submit to the relevant examination office. Students are responsible for submitting the correct certificate of achievement to you for signature. 

For your information: The relevant forms for students within the department and exchange students of the Master's progrm "Sociology - European Societies" can be found here.