Issues in relation to which referendums are mandatory at the national level

Benin
Constitution (1990)
http://www.cour-constitutionnelle-benin.org/lacourpresent/decrets/Constitution.pdf
Art. 155. -La r?vision n'est acquise qu'apr?s avoir ?t? approuv?e par r?f?rendum, sauf si le projet ou la proposition en cause a ?t? approuv? ? la majorit? des quatre cinqui?mes des membres composant l'Assembl?e Nationale.
If4/5 of the national assembly approve the proposal in question it will pass atthat point, if not it must be put to a referendum in order to pass.