Aside from the books mentioned elsewhere on the forum, there are some Germany-specific books e.g. those by Luise Reddemann that have not been translated into English.
1) Trauma heilen by Prof. Dr. Luise Reddemann and Dr. Cornelia Dehner-Rau, ISBN 978-3-8304-6171-5.
Approachable, easy to understand and start doing. Covers ptsd and cptsd, as well as therapy types available in Germany.
2) Eine Reise von 1000 Meilen beginnt mit dem ersten Schritt by Prof. Dr. Luise Reddemann.
3) Imagination als heilsame Kraft by Prof. Dr. Luise Reddemann.
As far as I remember, a bit theoretical. There's also a CD with the same title comprising imagination exercises, which is very practical.
Some of the books mentioned elsewhere on the forum are available in the original English or in German translation via inter-library loan in Germany.
The book that helped me a lot at the beginning of my therapy is:
"Das PTBS-Arbeitsbuch: Wirksame Techniken zur Überwindung von Symptomen traumatischer Belastung" von Mary Beth Williams (Autor), Soili Poijula (Autor), Theo Kierdorf (Übersetzer), Hildegard Höhr (Übersetzer)
ISBN-13 : 978-3981338928
This is the German translation of "The PTSD Workbook. Simple, Effective Techniques for Overcoming Traumatic Stress Symptoms"