The Holocaust was a gradual process. The Nazis didn’t start mass extermination when they got into power. But gradually prepared the population by dehumanizing the Jewish people. Segregation, as shown in this photo, was part of this.
The point was not to provide a bench for Jews, it was to segregate the benches so that non-Jewish Germans would not have to sit on a “contaminated” bench.
Being treated like below human life for years beforehand was terrifying and probably emotionally exhausting. This photograph was taken in Austria days after the Nazi annexation (March 1938). Also, it should be für instead of fur. But probably the low resolution makes it difficult to see the umlaut.
After January 1933, the Jews became the “Untermenschen” – the sub-humans. Jews were no longer allowed to visit restaurants, theaters, concerts, exhibits, movies, or swimming pools. They were not allowed to sit on park benches unless they were willing to sit on a few benches painted yellow and reserved for them. By 1934, all Jewish shops were marked with the yellow Star of David or had the word “Juden” written on the window.
How the Jews were identified? Germany has had birth records that prove someone’s identity way earlier than the Third Reich. Those records referred to the nationality or faith of a citizen. The Nazis were masters at fetching that data to calculate how much percent Jewish everybody was.
Additionally, Jews had and a lot of times still have very distinguishable names. They were also a lot more religious than the average Christian German. They held up their traditions and because some of those were not compatible with average German/Christian life they stuck to other Jews so often times they weren’t integrated into the community anyway. Those were things that made them stand out.
Also hating on Jews was a thing going on in Europe since the Middle Ages. It didn’t start with the Nazis. Even before the Nazis came to power people considered Jews weird because of their different traditions. So when Nazis came to power, everyone already knew who was a Jew. It wasn’t like this had to be newly found out.
The Nazis also demanded an “Ariernachweis” (Aryan certificate), a document that certified that a person was a member of the Aryan race. Beginning in April 1933 it was required from all employees and officials in the public sector, including education. With this document, someone could prove that his parents and grandparents were Germans. One way to check if someone was German was to check if his parents/grandparents were baptized.
(Photo credit: Institute for Contemporary History and Wiener Library).