The Nazi used this to tell if you where Jewish or not. It didn't work all the time and some Jews would have fake ideas to treat the Nazi. It also showed if you where pure jerman and it stated they you where the aloud to marry any none jerman people so the blood of the jerman would stay pure jerman. If they found out you where Jewish they would take you to camps and you would get killed there or some Jews would work for them.
1.Marriage between Jews and subjects of the state of German or related blood are forbidden. Marriages nevertheless concluded are invalid, even if concluded abroad to circumvent the law. Annulment proceedings can be initiated only by the State Prosecutor.
2.Extramarital intercourse between Jews and subjects of the state of German or related blood is forbidden.
3.Jews may not employ in their household female subjects of the state of German or related blood who are under 45 years old.
4.Jews are forbidden to fly the Reich or National flag or to display the Reich colors. They are, on the other hand, permitted to display the Jewish colors. The exercise of this right is protected by the State.
5.Any person who violates the prohibition under I will be punished by a prison sentence with hard labor. A male who violates the prohibition under I will be punished with a prison sentence with or without hard labor. Any person violating the provisions under III or IV will be punished with a prison sentence of up to one year and a fine, or with one or the other of these penalties. The Reich Minister of the Interior, in coordination with the Deputy of the Führer and the Reich Minister of Justice, will issue the Legal and Administrative regulations required to implement and complete the Law. The Law takes effect on the day following promulgations except for III, which goes into force on January 1, 1936. Nuremberg, September 15, 1935 at the Reich Party Congress of Freedom.
Propaganda was a type of trash talking. We speared propaganda threw social media. Mostly the Nazi made posters of Jews and deskribing how to tell if they are a Jew or not. Also the United States made posters saying if you know something about an attack don't tell anyone because you don't know if they are a spy or not.