Studied drawing at the Academy of Fine Arts in Brussels (1951) and painting at the Academy of Fine Arts in Warsaw (1952–57). After returning to Belgium, Gilles got involved in a wide range of creative work, such as commercial window displays, exhibition stands at trade fairs, setting up exhibitions, etc. (1957–60). He was an art director at the André François advertising agency (1960–63). Interested in matters of visual identity and institutional communication, he practised as a graphic designer (1963–82). Fiszman was the president of CBG, the Belgian Chamber of Graphic Designers (1975–78). He was a professor of graphic information processing at ENSAV (National High School of the Visual Arts), La Cambre, Brussels (1983–89). He set up the Axion Design Partnership in Montreal and San Francisco and Axion Fiszman & Partners, Brussels in 1982.