You must be able to credibly demonstrate a legitimate interest.
A legitimate interest is any public or private, idealistic or economic interest that is recognised by the legal system as worthy of protection. The confidentiality interest of the person sought must be taken into account in the decision.
The legitimate interest exists, for example, if the data is required for legal prosecution or defence (for example Dunning proceedings, legal action). This also includes the verification of personal details provided by a borrower by a credit institution. Extended civil register information can also be issued if the data is required for a serious research project.
The registration authority also requires information about the person in question, such as surname, first name, previous address(es) and date of birth. The provision of extended civil register information is only permitted if the person sought can be clearly identified on the basis of the information provided in the enquiry about the surname, former surname, first names, date of birth, gender or an address. You must also declare that you will not use the data for advertising or address trading purposes.