La Chaux-de-Fonds, Le Corbusier’s birthplace, is one of the few planned cities in Switzerland built on a geometric grid pattern. This modern city plan is closely linked to the city’s function as a centre of the watchmaking industry. The geometric structure used space efficiently. It also ensured the long rows of windows in the houses were oriented optimally, providing the light necessary for precise work. Although Le Corbusier never directly addressed this topic, it is likely that his thought on urban planning was inspired by the layout of La Chaux-de-Fonds.

The Modulor was a standardised measurement system Le Corbusier developed between 1942 and 1955, intended as an alternative to the metric and imperial systems. Le Corbusier aimed to promote the international standardisation of technical and architectural building elements.

The Modulor is based on standard human (male) measurements and the golden ratio. The scheme shows a stylised figure with an outstretched arm, flanked by two vertical scales. The red scale is based on the navel height (1.13 metres), and the blue scale corresponds to twice the navel height (2.26 metres).

Le Corbusier used this measure to design the proportions of rooms and buildings as both functional and aesthetically pleasing. This system creates harmoniously proportioned measurements, although they appear small by today’s standards.

The search for the Modulor measurement system was a long process that involved many people. The art historian Elisa Maillard played a key role. She had recently published a book on the golden ratio, and assisted Le Corbusier in the development of the Modulor. Her complex drawing of circles, sections, and squares provides Le Corbusier with the base of his system into which he only needs to insert the human figure.

In this drawing, which he called "Game," Le Corbusier shows the infinite possibilities of the Modulor measurements: a surface can be subdivided in various ways. In practice, these measurements could be used to subdivide window panes, for example.

Le Corbusier was convinced that unobstructed traffic was crucial to a functioning city. Traffic should circulate in a city like blood in the body. The plan of the ville radieuse ("radiant city") therefore included separate traffic arteries: fast and slow traffic would each have their own roads, and people could move safely on walkways through the city.

The "îlots insalubres" (unhealthy islands) were run-down and overpopulated areas in Paris that were classified as unsanitary due to poor living conditions. Classified in the early 20th century, these areas were to be redesigned at the request of the city.

Le Corbusier’s plan for such an "unhealthy island" involved replacing the existing buildings with high-rises, thus solving social problems. Like almost all of Le Corbusier’s urban proposals, this plan was never implemented due to political and financial obstacles.

The ville contemporaine (‘Contemporary City’) of 1922 is Le Corbusier’s first publicised design of a city. It is not intended as a concrete development plan, but as a utopian vision for a new city and society in the spirit of the avant-garde.

This vision differed drastically from anything known at the time. The city’s centre was to consist of huge high-rise settlements made of reinforced concrete, surrounded by green thoroughfares. The "contemporary city" pushed the technological advances of the time to the limit. Embodying the vision of freeing people from the "chaos" and cramped living conditions of industrial cities, it followed rational criteria to reorganise society and improve people’s lives.

The Unité d’habitation ("Housing Unit") was a type of residential block developed by Le Corbusier, conceived as a "vertical city." The concept emerged in response to the urgent need for housing after the destruction of World War II. Le Corbusier wanted to use the reconstruction to create a new form of urban living that met both individual needs and community life, thus enabling a better life. Unité d’habitation buildings were realised between 1947 and 1965 in Marseille, Rezé, Briey-en-Fôret, Firminy, and Berlin. They included facilities such as shopping streets and hotels, sports facilities, and kindergartens. With their monumental form, flat roofs, and various structures, they appear like passenger steamships in the landscape.

Colour schemes played an important role in Le Corbusier’s buildings. Le Corbusier developed two colour collections for the Swiss company Salubra, the first in 1931 and the second in 1959, consisting of a total of 63 shades. They were also used in the Unités d’habitation. The balconies of the apartments were painted in bright colours like blue, red, and yellow to create visual accents and break up the regularity of the concrete construction. In the interiors, colours designated different areas and provided orientation.

This model illustrates the construction principle behind the Unités d’habitation: like drawers or wine bottles in a rack, apartments of varying sizes are inserted into the block. Most of them are designed as two-storey "maisonettes." Each apartment spans two floors. The living room has a double-height ceiling and a huge window expanse for the time – even by today’s standards. All apartments extend from one side of the building to the other, allowing for optimal lighting and ventilation.

In the late 1920s and early 1930s, numerous architects from Western countries were active in the Soviet Union. They participated in urban planning and dreamed of the possibility of creating an entirely new world on a "rational" basis. Le Corbusier also participated and developed a proposal for the urban development of Moscow.

This resulted in the vision of the ville radieuse ("Radiant City"). This theoretical city plan envisioned various zones: business, residential, and recreational areas were strictly separated. Traffic arteries for different modes of transport connected the various parts of the city. Large green spaces were intended to ensure a healthy living environment. Increased building density maximised open and green spaces. The model was never fully realised but influenced various urban projects worldwide.