The Mondial chair was exhibited in the Dutch pavillion during the World Exhibition in Brussels in 1958. The pavillion was designed by Gerrit Th. Rietveld who collaborated on this project with interior-architect Sem Aardewerk. The Mondial chair was awarded a price at the Triënale in Milan in 1958.
For comparison see:
Peter Vöge, The complete Rietveld furniture, Rotterdam 1993, p.
158 and 159, no. 344
Marijke Küper and Ida van Zijl, Gerrit Th. Rietveld 1888-1964, Het volledige werk, Utrecht 1992, p. 285, no. 532
Barbara Laan, André Koch, Collectie Gispen meubels, lampen en
archivalia in het NAi 1916-1980, Rotterdam, 1997, pp. 125-126 for the steel and aluminium prototype and for an illustrated sketch for the
World Exposition with armchairs in situ and a photograph of the
exposition space with chairs without arms in situ.