If you have several residences in Germany and the status of your residence has changed (main residence is now used as a secondary residence or secondary residence is now used as the main residence without any move-in or move-out to a new residence or from a previous residence), you are required to notify the relevant registration office.

Main residence is:

• If you are married or in a civil partnership: the predominantly used home of the family or the civil partnership. This also applies if you are only temporarily living apart from your family or civil partner.
• If you are married or in a civil partnership and live permanently separated: Your predominantly used home.
• If you are a minor: the predominantly used home of your parents or foster parents. If they live separately, the main residence is the residence in which you mainly live.
• Only if the predominantly used dwelling cannot be determined beyond doubt, the focus of the living relationships is to be taken into account. Indications for this are, for example, the type of dwelling, personal ties, social and communal political activities as well as membership in clubs and other organizations.

At the same time, you are required to inform the registration office of any other residences (secondary residences) you have in Germany in addition to your main residence.

A secondary residence is any other residence in Germany. You can therefore have one main residence and several secondary residences.