Before and after international commissions he was head of the Legal Department of the Ministry for Foreign Affairs from 1949 to 1954 and again from 1961.During the 1930s, in Stockholm, as a secretary of state, von Numers interfered with the so-called Maydell affair, for example, by granting Nansen passport to Russian citizen residing in Germany, Baron Karl Frederick Karl Viktor von Maydell-Felks (born 1899) who was dubious to make a film in Finland.