German nationality law

German nationality law is the law governing the acquisition, transmission and loss of German citizenship. The law is based on a mixture of the principles of jus sanguinis and jus soli. In other words, one usually acquires German citizenship if a parent is a German citizen, irrespective of place of birth, or by birth in Germany to parents with foreign nationality if certain requirements are fulfilled. Naturalisation is also possible for foreign nationals after six to eight years of legal residence in Germany. However, non-EU and non-Swiss citizens must usually renounce their old citizenship before being naturalised in Germany. Citizens of other EU countries and of Switzerland usually can keep their old citizenship (see section "Dual citizenship"). Some EU countries do not allow dual citizenship even with other EU countries.

A significant reform to the nationality law was passed by the Bundestag (the German parliament) in 1999, and came into force on 1 January 2000. The reformed law makes it somewhat easier for foreigners resident in Germany on a long-term basis, and especially their children born in Germany, to acquire German citizenship.

The previous German nationality law dated from 1913. Nationality law was amended by the Nuremberg Laws of Nazi Germany; these amendments were revoked after the defeat of Nazism by an Allied occupational ordinance in 1945. Germany ratified the European Convention on Nationality, which came into force in Germany on 1 September 2005. All German nationals are automatically also citizens of the European Union.

Before the formation of the German Empire in 1871, the states that became part of the empire were sovereign with their own nationality laws, those of the southern ones (notably Bavaria) being quite liberal. Prussia's nationality law can be traced back to the "Law Respecting the Acquisition and Loss of the Quality as a Prussian subject, and his Admission to Foreign Citizenship" of 31 December 1842, which was based on the principle of jus sanguinis. Prussian law became the basis of the legal system of the German Empire, though the state nationality laws continued to apply, and a German citizen was a person who held citizenship of one of the states of the German Empire.

...
Wikipedia