Stephen Halbrook uses the occasion of the 75th anniversary of Kristallnacht to write of how the Nazis made use of gun registration:
Historians have documented most everything about [the Holocaust] except what made it so easy to attack the defenseless Jews without fear of resistance. Their guns were registered and thus easily confiscated.
To illustrate, turn the clock back further and focus on just one victim, a renowned German athlete. Alfred Flatow won first place in gymnastics at the 1896 Olympics. In 1932, he dutifully registered three handguns, as required by a decree of the liberal Weimar Republic. The decree also provided that in times of unrest, the guns could be confiscated. The government gullibly neglected to consider that only law-abiding citizens would register, while political extremists and criminals would not. However, it did warn that the gun-registration records must be carefully stored so they would not fall into the hands of extremists.
Note that it is not just gun control but the very act of registration that the Nazis were able to make use of.The ultimate extremist group, led by Adolf Hitler, seized power just a year later, in 1933. The Nazis immediately used the firearms-registration records to identify, disarm and attack “enemies of the state...”