This thesis addresses the question of the conservation of historic cities in central Iran, mainly built in raw earth, now less adapted to changing lifestyles and inserted into a modern, extensive and fragmented urban fabric. The thesis reveals the close relationships between the historic city, its domestic architecture, traditional society, its social and family structure, customs such as ceremonies and festive rites which run through the life of the urban population. Heritage is clearly studied here through the prism of its history and the values ​​of traditional society which aspires to both modernity and the conservation of its cultural heritage, thus having to confront antagonistic and complex issues to integrate its heritage into a process of cultural and social evolution.

Faced with the challenges of the development of the modern city, the tourism industry and globalization, the preservation of the cultural, social, economic and scientific values ​​of historic Iranian cities, to transmit a heritage exposed to a high risk of degradation due to major changes, to developments which induce requalification at different scales (architecture, city and territory), constitute a major challenge for Iranian society. As a result, the research analyzes the specific qualities of a heritage which has defined its characters in a close and harmonious relationship with a desert environment.

It demonstrates that it would be appropriate to rely on knowledge and know-how of great proven intelligence but today threatened with extinction while they remain fully relevant to the challenges of sustainable development. As a concrete illustration, the thesis uses the case study of the city of Yazd, particularly representative of the issues covered by the research and at the heart of the paradox between urban development and conservation. It highlights the need for an integrated, holistic and multidisciplinary approach for the conservation of historic cities in central Iran.