You can find trauma therapists on the following lists:
1) www.therapie.de/psychotherapie/-verfahren-/traumatherapie/
2) www.emdria.de www.emdria.de/therapeuteninnen
3) a little list of therapists in Germany with qualifications from the Swiss Institute for Psychotraumatology https://psychotraumatologie-sipt.ch/netzwerk/sipt-therapeutinnen
4) www.degpt.de/hilfe-fuer-betroffene/therapeut-innen-in-ihrer-naehe-finden/
Note that not all trauma therapists are on these lists and not all therapists on the lists are a good fit for everyone.