This research studies the physical transformations of heritage cities in Southeast Asia with the aim of understanding how heritage recognition and the contemporary rise of tourism shape architecture and urban space. My main hypothesis is that projects implemented in heritage cities (conservation and enhancement projects; projects for new buildings as well as urban planning) refer both to local forms and external types, models and procedures. Their encounter generates hybrid architectural and urban forms which originally combine, negotiate and weave together elements coming from different backgrounds.

Different kinds of exogenous elements are involved in the design of these projects:

- Internationalized construction types, introduced in the cities by national and foreign investments, strive towards the modernization of the urban landscapes.

- Dominant heritage paradigms, globally disseminated by international organizations such as UNESCO and ICOMOS, are based on European cultures. They were firstly imported in Asia by the colonial administrations during the 19th and the 20th centuries. Later, independent Asian Nation States have deliberately referred to them in the processes of heritage recognition and management.

I will examine this hypothesis for the city of Hoi An (Vietnam). Hoi An is a Sino-Japanese trading post which flourished between the 15th and the 19th century. By the end of the century, the rise of other ports on the Vietnamese coast, and the silting of Hoi An’s harbour, led to the eclipse of its commercial status. Hoi An’s built heritage is made up of the houses and the temples of the foreign communities which settled down in town because of the alternating monsoon winds on which foreign communities depended for the navigation of their boats (Huynh, 2011). The 30ha historical core, which also encompasses the French colonial district, was listed as a World Heritage Site in 1999. Since then, nationally-led conservation programs have managed urban transformations in the protected areas, while the town has been expanding around them: the last master plan frames1 782ha urban development and integrates Hoi An in the agglomeration of Dien Ben District (1100ha).

 This research aims to temper the widespread hypothesis according to which urban landscapes throughout the world are on their way towards homogeneity. This hypothesis has been put forward about contemporary urbanization processes, which would produce anonymous places (Augé, 1992) and elusive spatial shapes stretching out between the compact cities and the countryside (Sieverts, 2004; Mangin, 2004). It has also been assumed in researches on historical cities, which have criticized their «museification» (Assion, 2002) or their «unescoization» (Berliner, 2010).

 Rather, I will argue that projects in heritage cities are fields of exploration, where Southeast Asian cultures consciously interact with external elements and produce innovative cityscapes using the resources of local heritages.