Certificate of no impediment to marriage
The certificate of no impediment to marriage is required for marriages in a country other than Germany.
Germans who wish to marry in a foreign country shall apply for the certificate of no impediment to marriage at the registry office of their residence in the Federal Republic of Germany. If a foreign citizen wants to marry in the FRG, he or she has to present a certificate of no impediment to marriage of his or her home country. In this certificate the authority of the home country has to confirm that there is no legal impediment to marriage. If a country does not issue a certificate of no impediment to marriage for its citizens, an exemption from this certificate can be applied for at the competent Higher Regional Court via the registry office of the fiancées in connection with the registration of the marriage.
The registrars are happy to advise you.
§ 39 and § 12 section 3 Law of Civil Status (Personenstandsgesetz, PStG) as well as § 1309 German Civil Code (Bürgerliches Gesetzbuch, BGB)