What is the legal basis for video surveillance in public space in Switzerland?

Art. 13 of the Federal Constitution (protection of privacy), the Data Protection Act (FADP/DSG) with its strict requirements for purpose limitation, transparency and proportionality, the cantonal police laws, and rulings of the European courts.

• Federal Constitution (BV) Art. 13, protection of privacy:
  1. Everyone has the right to respect for their private and family life, their home, and their mail and telecommunications.
  2. Everyone has the right to protection against the misuse of their personal data.
• Data Protection Act (DSG): strict requirements on purpose limitation, transparency and proportionality. They apply to private persons too, not just the state.
• Cantonal police laws (e.g. Zurich, Lucerne, Basel-Stadt).
• Rulings of the CJEU and ECtHR (EU Court of Justice, European Court of Human Rights):
  • Bodycams: only allowed when there is a concrete danger.
  • Dashcams: only occasionally, not permanently.
  • Drones: strict purpose limitation, no surveillance of the neighbourhood.

Go deeper:

• Federal Constitution of the Swiss Confederation (Fedlex, English) — Art. 13 on the protection of privacy.
• FDPIC (EDÖB): Videoüberwachung durch Private — the federal data-protection authority on when private filming is allowed.