What were some of the restrictions that Hitler placed on German Jews?

is the answer prohibited from marrying non jews, attending German schools, and practing law.

Yes, that was the start of the Jewish persecution. This site has more details.

http://www.historyplace.com/worldwar2/triumph/tr-boycott.htm

Later, all Jews were required to wear a yellow Star of David.

That's correct. Hitler's regime imposed several restrictions on German Jews during the Nazi era. Some of the key restrictions included:

1. Prohibition on Marrying Non-Jews: The Nuremberg Laws enacted in 1935 banned marriage between Jews and non-Jewish Germans.

2. Exclusion from German Schools: Jewish students were gradually expelled from German schools and universities, subsequently leading to the establishment of segregated Jewish schools.

3. Ban on Practicing Law: Jewish individuals were prohibited from practicing law or holding government positions, which greatly limited their professional opportunities.

However, it's important to note that these restrictions were just a few examples of the systematic persecution and discrimination faced by German Jews under the Nazi regime. These policies were part of a wider campaign to marginalize, dehumanize, and ultimately eradicate the Jewish population in Europe.