According to the EU drone regulation, if I fly a drone equipped with a camera or sensor which is capable of recording personal data, I am required to register with the official operator registry UAS.gate*.
*Switzerland has not yet adopted the EU drone regulation, registration is therefore voluntary and free of charge for drone pilots in Switzerland until further notice.
Further information on the current situation for Swiss drone pilots in terms of registration, training and exam are available in the FAQ (section "Motion 20.3916 and the application of the EU drone regulation in Switzerland").