Two treaties provided the protection for refugees coming from Germany: the Provisional Arrangement concerning the Status of Refugees coming from Germany, signed in Geneva on 4 July 1936 and the Convention concerning the Status of Refugees coming from Germany, signed in Geneva on 10 February 1938.
An Additional Protocol to these treaties, opened for signature in Geneva on 14 September 1939, extended them to include refugees from Austria. As refugees from Germany were not entitled to Nansen certificates, these treaties provided for a separate identity certificate. The Convention of 1938 was likewise modelled on the Convention of 1933.
Neither the Provisional Arrangement of 1936 nor the Convention of 1938 mention the expression refoulement, and their provisions on asylum are weaker than those of the 1933 Convention. It was even laid down that, in extreme cases, refugees could “be sent back across the frontier of the Reich”.
Taken from: Gilbert Jaeger: On the history of the international protection of refugees, Form IRRC September 2001 Vol. 83 No 843 727:
You can find the full text of the Convention in the pdf-document on the left side.