In 2018, the world population is around 7.6 billion, 4.2 billion in urban settlements and 3.4 billion in rural areas. Of this total, according to UN-Habitat, 3.2 billion of urban inhabitants live in southern countries. Of them, one billion, or nearly a third, live in slums. Urban poverty is therefore an endemic problem that has not been solved despite all initiatives taken to date by public and private sectors. This global transformation of our contemporary societies is particularly challenging in Asia and Africa, knowing that on these two continents, less than half of the population currently lives in urban areas. In addition, over the next decades, 90% of the urbanization process will take place in these major regions of the world. Urban planning is not an end in itself. It is a way, human and technological, to foresee the future and to act in a consistent and responsible way in order to guarantee the well-being of the populations residing in cities or in their peripheries. Many writers and urban actors in the South have criticized the inadequacy of urban planning to the problems faced by the cities confronting spatial and demographic growth. For many of them the reproduction of Western models of planning is ineffective when the urban context responds to very different logics. It is therefore a question of reinventing urban planning on different bases. And in order to address the real problems that urban inhabitants and authorities are facing, and offering infrastructures and access to services for all, this with the prospect of reducing poverty, to develop a more inclusive city, with a more efficient organization, in order to make it sustainable, both environmental than social and economic. The field work carried out during recent years in small and medium-sized cities in Burkina Faso, Brazil, Argentina and Vietnam allows us to focus the attention of specialists and decision makers on intermediate cities that have been little studied but which are home to half of the world's urban population. From local diagnoses, we come to a first conclusion. Many small and medium-sized cities in the South can be considered as poor cities, from four criteria. They have a relatively large percentage of the population is considered to be poor; the local government and its administration do not have enough money to invest in solving the problems they face; these same authorities lack the human resources to initiate and manage an efficient planning process; urban governance remains little open to democratic participation and poorly integrates social demand into its development plans. Based on this analysis, we consider it is imperative to renovate urban planning as part of a more participatory process that meets the expectations of citizens with more realistic criteria. This process incorporates different stages: an analysis grounded on the identification of urban investment needed to improve the city; the consideration of the social demands; a realistic assessment of the financial resources to be mobilized (municipal budget, taxes, public and international external grants, public private partnership); a continuous dialogue between urban actors to determine the urban priorities to be addressed in the coming years. This protocol serves as a basis for comparative studies between cities in the South and a training program initiated in Argentina for urban actors in small and medium-sized cities, which we wish to extend later to other countries of the South.