Hanoi, the capital of Vietnam, has been the symbol of national pride since it had been decided as the capital in 1010 by Ly Dynasty until early 19c. This study aims to disclose various ways of constructing townscapes of Hanoi suitable for the capital city of Indochinese Union after French imperialism's invasion in late 19c. Focused on the public monuments and public buildings which played important role to construct impressive townscapes, this study analyzed photos and maps of colonial era and found following results. The public monuments based on figurative forms expressed three subjects like, first, the nation of France or Indochinese Union, second, the french persons related to Indochinese colonial domination, third, the wars of France. The dominating townscapes of colonial Hanoi were vistas consisting of streets and public buildings throughout the city. By tracing the process of constructing the public buildings and surrounding streets through the maps published in various periods of colonialism, the vistas in colonial Hanoi were found to have been constructed in various tactful ways as following. First, the public building was arranged using the one-ended street or bended street to create vista effect. Second, public building was placed in the middle of existing street to create vista. Third, new short street was constructed in front of public building to make the building as focus of vista. Fourth, public buildings were placed at both ends of a street to make a double vista. Fifth, new public space was constructed to make the central axis of the public space coincide with the axis of public building. The vistas created by above mentioned various ways were able to exclusively attract public gaze of the people moving along urban streets. It is notable that the vistas of Hanoi had been constructed individually and persistingly over in a long time without conforming to any particular master plan. This study, which has analyzed the way and process how the French colonialism had been embodied as townscapes in urban space of Hanoi, is expected to expand the understanding of Asian cities of colonial period and to provide a new way of reading contemporary Asian cities which still contain the urban space and townscape constructed during colonial period.