(Not to be confused with the Spanish rock band or German jazz fusion band of the same name).
Niagara was a synthpop / rock band from Rennes, France that was active from 1984 to 1993 that starred musicians Muriel Moreno and Daniel Chenevez.
This pin is based on the band's logo from their third album 'Religion'. According to one source, this specific pin was released sometime around the same year as the band's third album in 1990. This pin also originally came with a gold coloured butterfly clasp.
Source: http://www.pins-museum.com/pages/egf/autres-fabricants/afers.html