Nuremberg Laws
Hitler changed the laws to nullify the degrees of Jewish professionals. Doctors, lawyers, and dentists could not pursue their respective careers, except with Jewish clients.
For example, this letter, sent from Dr. Alfred “Israel” Karpen, includes the text “Licensed solely for the legal counseling and representation of Jews” in the lines below the return address. Dr. Karpen could serve only as an advisor (Konsulent) to Jewish clients. (NOTE: The title doctor [Dr.] applied to lawyers in this era.) Even if a lawyer had many Aryan clients, he could not practice law on their behalf.