A domicile is a place where the individual maintains a residence under circumstances, which indicate that he will keep and use it on a more than temporary basis.
Habitual place of abode
The habitual place of abode of an individual will be established if the person is physically present on a long term basis in Germany. Persons are resident in any case in Germany if they stay longer than six months in Germany, where short interruptions of the presence in Germany won´t be taken into account. If the employee has his domicile or habitual place of abode in Germany, then he is fully taxable in Germany. German resident taxpayers are subject to tax on their worldwide income. Double taxation will be avoided in accordance with the applicable tax treaties.
Individual nonresident taxpayers are subject to tax in Germany on their German sourced income. Nonresidents can apply to be treated as a resident if their German income is at least 90% of their total worldwide income or when the worldwide income, which is not subject to taxation in Germany, is less than €9,168 (adjustments for foreign tax basis calculations are necessary for several countries). For spouses of residents living in the EU/EEA it is also possible to claim a classification as resident if the joint income contains income which arises almost entirely in Germany.