L. G. Pineau arrived in Ha Noi in 1930 to face a colonial government more concerned with administration than development. The time for large-scale construction projects had passed. Pineau, who was more at ease with urban planning than architecture, concentrated on renovating historical neighborhoods by analyzing every city block and working with existing structures. In addition, he conceived the western and southern growth of Ha Noi. Pineau's L'Urbanisme en Indochine (1943) defined a philosophy of contextual intervention by recognizing the pertinence, function, and culture of a mercantile city and accepting its fundamental heterogeneity. Urban planning in Ha Noi shifted from the prioritised programmatic rationalisation of commerce and climatic conditions in Hebrard's masterly architecture to Pineau's questions about civilisation and the preservation of traditional lifestyles.
In 1940, the Japanese took over Indochina but kept a French administration until March 1945. During the Japanese occupation, the French upper echelon began to use architecture as a "social corrector." Jean Decoux, who served as French governor general during this period, attempted to reinforce French power by constructing huge State buildings. Designers tried to bring back the hybrid theme so important to Hebrard. However, the demands of the time gave way to an official style favouring massiveness and symmetry within the limits of a strongly regulated functionalism but with curved roofs to express the city's "Vietnameseness."