In 1928, the French Minister of Labour, Louis Loucheur, won the passage of a French law on public housing, calling for the construction of 260,000 new housing units within five years. Le Corbusier immediately began to design a new type of modular housing unit, which he called the Maison Loucheur, which would be suitable for the project. These units were in size, made with metal frames, and were designed to be mass-produced and then transported to the site, where they would be inserted into frameworks of steel and stone; The government insisted on stone walls to win the support of local building contractors. The standardisation of apartment buildings was the essence of what Le Corbusier termed the "Ville Radieuse" or "radiant city", in a new book which published in 1935. The Radiant City was similar to his earlier Contemporary City and Plan Voisin, with the difference that residences would be assigned by family size, rather than by income and social position. In his 1935 book, he developed his ideas for a new kind of city, where the principle functions; heavy industry, manufacturing, habitation and commerce, would be clearly separated into their own neighbourhoods, carefully planned and designed. However, before any units could be built, World War II intervened.