As far as I understand, for acceptance into a doctoral program in Germany, there is no deadline - you have to find a "Betreuer" (advisor) with whom you would like to work and also determine if you meet the eligibility requirements. This includes language requirements and can vary. If you need additional German language training before commencing your program, there may be deadlines for that.
There is often a DAAD infopage in various countries and languages which briefly explains the application process for a PhD in Germany - you can do a search.