Introduction
In the wake of the Great War and subsequent defeat of Germany, a demilitarisation and popular disarmament was required by the victorious Entente members. Thus, regulation of 30th January 1919 required the introduction of the permits for all personal and hunting weapons and delivery of all unlicensed firearms. This regulation was not too eagerly carried out by German authorities, and thus, the new, more strict demands of immediate return of all privately-owned firearms under the threat of penalty was required during the Spa conference. Agreeing to honor the Spa Agreement, German authorities introduced new, stricter regulation on 7th August 1920 as well as the office of the National Commissar for Popular Disarmament. According to new regulations, all military weapons and handguns (along with spare essential parts) were to be immediately surrendered under severe jail penalties. Most sporting and hunting weapons were exempted from the new laws, however. This time, Germans attempted to disarm the population more diligently, but the increasing unrest and political upheaval in the early 1920s made the task hard to accomplish.
In 1927, the final regulations related to Versailles Treaty, came in effect. According to regulation of 27th July 1927, production of all handguns with barrels longer than 98 mm and caliber higher than 8 mm was prohibited throughout Germany (which was not much of a concern, as after the Locarno and Rapallo treaties, Germans opened production in USSR). Few months later, on 12th April 1920 a seminal National Weapons and Munitions Act (Reich Waffen und Munitions Gesetz) went into force, abolishing the general prohibition of purchase and ownership of firearms and introducing a regulatory practice of weapon purchase permits (Waffenerwerbscheine) that became the basis of modern German solutions (mainly Weapons and Ammunition Act of 1972) that were also adopted by other countries and now are de facto standard procedure in most European states. The new Act introduced the idea of purchase permit, a 'reliability' requirement (sometimes rendered as 'unblemished reputation' but all in all it was an equivalent to a background check) and a need to purchase. The latter was usually only a formality and in practice a simple declaration of 'personal protection' was accepted, especially given the volatile political situation. The violence resulting from the latter led however to the introduction of an special Weapon Abuse Act (Gesetz gegen den Waffenmissbrauch, GGWmb) on 28th March 1931, banning carrying any slashing or bashing weapons (truncheons, knives, swords etc.) in public places (GGWmb, §1, p.2) and forbidding people from carrying weapons while attending any political rally or similar event (GGWmb, §3. p.2), under a penalty of no less than 3 months jail time.
Rule of National Socialists
When the National Socialists seized power in 1932/1933, they largely upheld the Act of 1928 and the provisions of Weapon Abuse Act of 1931 that remained the groundwork for the gun control in Germany until 1938, when the new Act of 1938 was introduced, although it haven't changed basic rules by much. New rulings introduced in 1938 (RGBl 1938, part I, no. 31, pp. 265-269) served two main purposes. The first was militarization of the society, especially government employees, the other was further marginalization of Jews and minorities by denying them various rights.
As with the Act of 1927, to buy a handgun, as they were the most tightly controlled type of weapons available to civilians, as specified in §11 of RGBl, a citizen had to apply for a weapon purchase permit (Waffenerwerbschein) that was valid for one year and after the purchase, had to have a 'weapon permit' (Waffenschein) whenever he or she was carrying said weapon. It is important to note, that citizens working for several state agencies and services did not require weapon purchase permit issued by the police, but could use one issued by their employer, usually without any additional paperwork (the issuance was an internal procedure). This applied to all people employed directly by the central and provincial (Land) government, National Bank, National Highway Authority, Air Defence and National Socialist Air Corps. Furthermore, Air Defence, Technical Emergency Service (Technische Nothilfe), National Socialist Air Corps as well some departments of NSDAP and local associations that received the right to arm their members, were able to issue the internal weapon permits equivalent to the permits issued by police (§12). This was different from issuance of service weapons to the members of military, police and other peacekeeping services that was covered by the §18 of the Act. Each permit was valid for 3 years after which it had to be renewed (what usually was a formality).
It is worth noting that the requirements and regulations detailed above applied to handguns only, as the purchase and ownership of hunting rifles and shotguns (basically, any weapons save for military-issue rifles that were unavailable for private purchase and handguns that required permit) were basically not regulated save for age check, as it was still illegal to sell any weapons to minors. When speaking of the duty weapons issued for civilians, it is worth noting that some state-governed institutions had the right to arm their members. For example, all members of the SA, members of NSDAP from the rank of Ortsgruppenleiter (Local Group Leader), NS-Kraftfahrtkorps members (Motor Corps, German equivalent to Automobile Associations) from the rank of Sturmführer up and Hitlerjugend members from the rank of Bannführer up were able to receive personal firearms from the authorities of their respective services.
Who could apply for the weapon permit? Basically any adult German citizen (i.e. at least 18 years old) who presented a specific need (personal defence, home defence, training, sport etc.) and gave no 'doubts to reliability' which was generally a relic of the older rulings and generally meant a good conduct related to law and peace (no arrests or criminal record, no suspicions of anti-government activities, lack of debts etc.). The latter were nor hard and fast rules precluding the citizen from obtaining a handgun, but rather an loophole allowing authorities to deny permit to people they considered potential troublemakers.
Furthermore, §15 of the Act detailed all people who could not obtain weapon permits. These were: people found mentally ill or diagnosed with developmental problems, Gypsies and all people with no fixed place of residence (described as 'people living in a Gypsy way'), people sentenced for treason, people for whom a existed a substantial evidence of anti-state tendencies (basically, members of all political organisations critical of NSDAP), people under police surveillance (it included not only those suspected of criminal activities, but also many of anti-Nazi political activists and known homosexuals) and people sentenced for any crime against health, peace or property as well as for any breach of hunting and fishing regulations to a jail time of more than two weeks (this preclusion was expunged after three years counting from the end of the penalty served).
Were there weapons unavailable for citizens? Yes. Most military-grade weapons, corresponding to class A weapons in modern European law (fully automatic weapons, flamethrowers, all types of artillery) were beyond the reach of a normal citizen. Furthermore, it was forbidden to manufacture, sell or possess any weapons that were specially designed to be easily collapsible 'beyond the use typical for sport or hunting' or disguised as objects not resembling weapons (canes, umbrellas etc.), all suppressed firearms and small caliber (.22" or 5.6 mm) hollow-point ammunition (§ 25 p.1.1-1.3). In all cases it was possible to get special permission to manufacture or possess such devices.