The rules for non-residents of Germany differ from residents. Filing a tax return may be more complicated if a person comes from a country with which Germany does not have an agreement to avoid double taxation.
This for example applies to some countries in Africa or even Afghanistan.
The basic rule for citizens from countries without an agreement states: taxes are paid wherever you are and for your entire income, including any rental income from your home country. Those who live and work in Germany for a shorter period (less than 6 months) are still subject to tax in their home country.
However, under certain conditions, people can be treated as subject to unlimited income tax in Germany.
The advantage is that you can use all personal tax benefits as well as a whole range of family-related benefits. These include the tax deduction of special expenses.
Allowances and special expenses can be for example: