You were born in Germany, or you got married there, and you need a new certificate? Or do you require a death certificate, divorce order, or other kind of certificate from Germany?
Civil status certificates can be obtained directly at the local registry office in Germany, divorce orders can be obtained directly at the divorce court. There is no central authority that can issue your certificate and you cannot apply for it at the German Missions abroad. You may contact the local offices through the website of the city or town, e.g. www.frankfurt.de, www.leipzig.de, etc.
Were you born abroad or did you get married abroad and did you subsequently register the birth or marriage with the Registry Office I in Berlin? Or did you hand in a name declaration at the Embassy, which was forwarded to Berlin, and you now require a new name certificate? Ordering certificates in Berlin