You need to provide a specific attestation issued by a Swiss representation, e.g. a certificate of nationality and registration.

In accordance with the Ordinance on Swiss Persons and Institutions Abroad, the Swiss representations abroad are authorised to provide attestations on the basis of established facts.

In this context Swiss representations are expected to check every request and to verify, among other things, if a local authority or institution is competent for drawing up a document and if Swiss interests are involved.

Detailed information can be found on the Spanish page.