1) they made them wear the Star of David on their clothes so they could be publicly ridiculed and they would know who is Jewish or off Jewish descent
2) Supply to Jewish people (like bread, eggs, sugar) was cut, aka not given to Jews or people of Jewish descent.
3) Jewish people were limited to communication due to Nazis saying on phone lines and trying to find out who is Jewish and who is not.
4) Nazis limited their freedom, due to putting them in concentration camps.