Honorary work ("Ehrenamt") is employment for charitable organisations without a wage or with only a very low one. You do not need any work permit for this work. If you are not sure whether these conditions have been met or whether your employment actually constitutes a job or internship, consult your immigration authority ("Ausländerbehörde").
Honorary work: a good way to find a proper job
Honorary work is highly regarded in Germany. Honorary employees often assume important tasks, such as helping new refugees. They distribute food and clothing, teach German and help children in the accommodation. If you already speak a little German, but have not yet found a job and think you could help other people, then you should contact the employees of the charitable organisations. Helpers are always needed and sometimes this later results in opportunities for a paid job.