Read here about Apostilles and where to get them.
What is an Apostille?
An Apostille is a confirmation of authenticity and allows for a documents (for example a birth certificate) to be accepted by authorities in another country. According to the Hague Convention of 5 October 1961, an Apostille is issued by the country which authorities have issued the original document. There is no other kind of legalisation of certificates from member states of the Hague Convention. Information on Apostilles and legalisation can be found here
Do you still have to apply for the original certificate?
Apostilles for South African Documents
Apostilles for South African documents are issued by the Department of International Relations and Cooperation:
Telephone: +27 (12) 351 1726 or -1268/9
Apostilles for German Documents
There is no central authority, instead, the competent Apostille authority varies from one federal state to another. We recommend inquiring at the office that issued your original document, as they will be able to tell you where to turn to for an Apostille for their certificate.
Further information can be found here