Erasmus students:
Unfortunately not. You will be allowed to choose among a large number of law courses.
In addition to that you can take one German language course (level A2 to C1) per semester and courses from the cultural program for incoming exchange students ("Berlin and Germany in a European Perspective") that the FU Incoming Team presented to you during the orientation days.
Themis students:
Unfortunately not. If you speak German though, you will be allowed to take one German language course (level A2 - C1) in addition to your Themis courses.
Overseas students and students from other exchange programs (i.e. DAAD scholars):
Yes, you are allowed to take courses from all departments and study programs for which you have been enrolled at Freie Universität Berlin. One German language course (level A2 to C1) and courses from the cultural program for incoming exchange students ("Berlin and Germany in a European Perspective") are also open to you.
However, courses from continuing education Master's programs (with tuition) might be excluded.