Are referendum results binding?

Finland
Answer
Optional referendum - never
Source
THE FINNISH CONSTITUTION
(Adopted1999; last amended 2011)
http://www.finlex.fi/fi/laki/kaannokset/1999/en19990731.pdf
Section 53, sub-section 1: The decisionto organise a consultativereferendum is made by an Act, which shall contain provisions on the timeof the referendum and on the choices to be presented to the voters.
Comment
Allreferenda are purely consultative.