§ 55 NDSG
Lodging a complaint with the supervisory authority
(1)1Any data subject who considers that his or her rights have been violated in the processing of his or her personal data by a controller or processor subject to supervision under the provisions of this Part may, without prejudice to other legal remedies, lodge a complaint with the authority headed by the Land Commissioner for Data Protection. 2This shall not apply to the processing of personal data in the course of judicial activities by courts within the scope of application of § 23(1). 3The data subject may be represented in the exercise of his or her right of complaint in accordance with Article 80 of the General Data Protection Regulation applied mutatis mutandis.
(2)The authority headed by the Land Commissioner for Data Protection shall inform the complainant of the progress and the outcome of the complaint and shall draw his or her attention to the possibility of judicial redress.
(3)1The authority headed by the Land Commissioner for Data Protection shall forward a complaint lodged with it concerning processing that falls within the competence of a supervisory authority in another Member State of the European Union without delay to the competent supervisory authority of the other State. 2It shall in that case inform the complainant of the forwarding and, at his or her request, provide further assistance.