Many public and private organisations, universities, federal states, districts and cities in Germany offer scholarships for students. Some of these scholarships are specifically for refugees. Most scholarships cover the cost of the semester fees, everyday living and possible tuition fees- and you do not have to repay them. Unfortunately, there is no complete database of scholarship programmes available in Germany- the German Academic Exchange Service (DAAD), however, has a database of scholarships for international students. You can also search for a scholarship on MyStipendium or Stipendienlotse websites.
Furthermore, foundations provide many scholarships at different levels. You can find an overview of scholarships provided by foundations on the webpage of the Federal Association of German Foundations ("Bundesverbands Deutscher Stiftungen"). As soon as you are enrolled at a university, you can seek advice from the students' union ("Studentenwerk") or take part in informational events concerning funding at your university.