A two-part referendum was held in Switzerland on 23 May 1875.[1] A new federal law establishing and certifying civil status and marriage was narrowly approved, whilst a new federal law on suffrage was narrowly rejected.[1] 
  Background
 This was the first optional referendum held in the country, as all previous referendums had been mandatory referendums.[2] Whilst obligatory referendums required both a majority of voters and a majority of cantons in favour, optional referendums required only a majority of the public vote.[3] 
 Results
 Federal law on the establishment of civil status and marriage
   | Choice  |  Votes  |  %  | 
  | For |  213,199 |  51.0  | 
  | Against |  205,069 |  49.0  | 
  | Invalid/blank votes |   |  –  | 
  | Total |  418,268 |  100  | 
  | Registered voters/turnout |   |    | 
  | Source: Nohlen & Stöver  | 
 Federal law on suffrage
   | Choice  |  Votes  |  %  | 
  | For |  202,583 |  49.4  | 
  | Against |  207,263 |  50.6  | 
  | Invalid/blank votes |   |  –  | 
  | Total |  409,846 |  100  | 
  | Registered voters/turnout |   |    | 
  | Source: Nohlen & Stöver  | 
 References
   - ^ a b Nohlen, D & Stöver, P (2010) Elections in Europe: A data handbook, p1902 ISBN 9783832956097 
  - ^ Nohlen & Stöver, pp1901-1902 
  - ^ Nohlen & Stöver, p1891