There is no such treaty. But Russia and Germany are participants of the Hague Convention of October 05, 1961. Any notarized and apostilled document will be accepted in any country participating in the Convention. Nevertheless, such document shall be accepted by a court only as a written proof but not as an evidence: evidence shall be given personally, orally and in public. In case you are a plaintiff, a defendant, an applicant, a third party or a victim you can issue a power of attorney to any person to read the case and such person will be authorized to witness for you in the court.