I have written about the vagaries of interwar German gun laws in this post.

The long and the short of it is that the assassination of the German diplomat Ernst vom Rath in Paris by a Polish-Jew Herschel Grynszpan in 7 November 1938 prompted a whole wave of new anti-Jewish legislation and popular violence against the Jews. This included the confiscation of weapons by the police and decrees limiting Jewish ownership of various weapons. However, it is dangerous and methodologically unsound to look at these confiscations in isolation and extrapolate "lessons" from it. The confiscation of weapons was part of a larger process of denying Jews any civil rights in Germany and was made much easier by earlier edicts like the Nuremberg Laws of 1935. Events like vom Rath's assassination provided a pretext for the state to further tighten down these restrictions, but the whole process had already begun with Hitler's seizure of power in 1933. The narrative "first they came for guns, then their civil rights" does not really apply to the German example.