The instructor needs to be an EASA instructor, not necessarily a German licence holder.
If you meet all the other criteria, ie hours & landings, the FI/CRI who does the 1 hour training flight can also endorse your licence with the new expiry date (no need for an examiner) if authorised to do so by the national authority that issued your licence. Some national authorities may not have authorised anyone, so check with your German instructor.