The obligation to have completed all subjects is regulated in Article 61 of the Study and Examination Regulations:
Under the course overview, the number of credits earned (including credits awarded) is listed under “Credits earned (including credits awarded):”; this number must be greater than or equal to 180 for the Bachelor’s degree, 120 for the Continuing Master’s degree, 240 for the 4-year Master’s degree, and 300 for the 5-year Master’s degree. Make sure you have selected the correct course of study in the top right.