Henry Massonnet, born January 6, 1922, in Oyonnax, France, was a famous French designer. He is particularly known for being the designer of the “Tam Tam” stool in 1981. He was Mayor of Mornay, and he was also a great collector of art. In 1948, he took over the family business called “Stamp” and he designed a new plastic molding process. He was a French engineer and entrepreneur and his company had about 340 employees. He designed the “Fauteuil 300” chair, defining style for a particular type of chair: the affordable Monobloc, which is injection molded as a single piece in a single step. Massonnet’s aim was to develop an all-plastic, easily stackable, weatherproof, durable, and affordable chair. The model was produced at Massonnet’s own company STAMP. By improving the efficiency of the manufacturing process, he was able to reduce the duration of the entire production cycle to less than two minutes. Typologically, the design can be traced back to the sheet steel chairs of Joseph Mathieu from the early 1920s, which already featured the typical inverted legs. Another predecessor is Helmut Bätzner’s 1966 Bofinger Chair the production method of which, however, was more complex. Massonnet died in Bourg-en-Bresse, December 27, 2005.