According to police records, the American tourist was extremely intoxicated, as indicated by a high blood alcohol level. The tourist's assailant escaped the scene of the attack and is being sought by law enforcement on charges of bodily harm.
The American citizen — whose identity is currently being withheld — is being investigated for violating German law that strictly forbids the use of Nazi symbols.
The man could face up to three years in prison as punishment in Germany for expressing Nazi symbols, although courts typically settle on fines for a first offense.
The Nazi salute, which was banned in Germany after World War II, is a greeting gesture used to express obedience to Adolf Hitler in Nazi Germany, a government that permitted and encouraged the killing of people who were of different racial or ethnic origin.
This is the second time this month that tourists have been arrested for demonstrating Nazi symbols in Germany.
One week ago, two Chinese tourists were fined some $600 apiece after giving Nazi salutes outside of the Reichstag, a historic edifice in Berlin.
In 2011, a 30-year-old Canadian was detained and fined for giving the Nazi salute in the same location.
This month the Switzerland Supreme Court convicted a man who was photographed giving the Nazi salute in front of a synagogue in Geneva.