Who cannot apply for German citizenship?

The application for German citizenship requires that the applicant is free of criminal offences and is committed to German values. Other exceptions must also be taken into account.

If you wish to apply for German citizenship, you must not have been sentenced to two or more years of imprisonment or juvenile detention (in Germany or abroad) and there must be no other grounds for exclusion under Section 11 StAG.

Before the naturalisation certificate is issued, a solemn commitment to the free democratic basic order and a declaration of loyalty must be made.

The German naturalisation authorities also point out the following further exceptions:

If German citizenship was subsequently acquired or re-acquired (e.g. through naturalisation) after being given up, lost or withheld as a result of persecution (1933 - 1945) and then lost again (e.g. through renunciation, dismissal, acquisition of another citizenship on application), German citizenship cannot be re-acquired through naturalisation in accordance with Section 15 StAG. This also applies to children who were born or adopted as children after the (renewed) loss of German citizenship.
However, naturalisation in accordance with § 15 StAG remains possible if the German citizenship acquired after 8 May 1945 was lost before 1 April 1953 through marriage to a foreigner or through legitimation by a foreigner in accordance with German law.