Foreign certificates must be handed in as officially certified copies with an officially certified translation. If your documents do not fulfil the requirements or if important certificates are missing, your application will not be processed. Notes on certification of documents: www.fau.eu/international/international-applicants/important-information/notes-on-certification-of-documents/ .
Documents don't have to be translated if they are issued in German, English or French.
Certificates that were obtained at German educational institutions, don't need to be certified and can be submitted as simple/uncertified copies.