Students from EU countries do not need a work permit to take up a job in Germany.
Students from non-EU countries may work a maximum of 120 full days (more than 4 hours a day) or 240 half days (up to 4 hours per day) per year. This work is then not subject to approval (you do not need a work permit). A special permit is required for an activity with more than 120 days of work per year.
The social counselling service of the Studierendenwerk Greifswald as well as the foreigners' registration offices of the cities of Greifswald, Stralsund and Neubrandenburg are available as contact persons for all questions regarding employment during your studies.