Copyright
Whenever scientists working in germany use others intellectual property, the way this property can be used is regulated in a special law to "harmonise the copyright law to the needs of a knowledge-based community" (Gesetz zur Angleichung des Urheberrechts an die aktuellen Erfordernisse der Wissensgesellschaft - UrhWissG). This law came into effect on March 1, 2018.
Basic information about what kind of usage is allowed can be found on the homepage of Heidelberg University (in German language).
Most important for our common cases and applications are sections §60a and §60c UrhWissG.
Basically, it is allowed without permission to copy, scan, digitise, store or prohibit (via copies/electronically) complete figures, images o r scientific articles, provided the source or name of the author is mentioned and usage is limited to teaching or research applications.
► If used during lectures, seminars or tutorials electronic access to copied intellectual property has to be under control or restricted , i.e. solely participants of your course/lecture have access via electronic keys (see e.g. MOODLE). It is allowed to distribute paper copies to course participants.
►It is allowed to use copies of intellectual property during teaching lessons to emphasize particular issues fo your lecture.
► It is allowed to use copied intellectual property within a closed group of people (e.g. your research group, electronically protected access) if this is required for your scientific research.
► An excellent explanation about common applications and cases can be found HERE (in German language).
In case you are not sure if your specific case may rise problems you should address your question to the ZAH Scientific Manager (Guido Thimm). He will try to solve your issue together with the university's legal department.
Important: comments and explanations above are neither complete nor can be considered as legal bindung statements.