The private-led diffusion of urbanization across greater territories and urban mega-regions raises questions about the capacity of public authorities to control urban development through planning. On the other hand, such urbanization processes are often informal – either illegal or pushing the boundaries of urban planning rules – and involve multiple actors, including public authorities, private investors, and property developers. Where they do exist, plans are rarely realized as expected due to unplanned transformations in the context in which they are to be implemented. Occasionally, such plans comply a posteriori with urban evolutions.
We aim to examine and compare the difficulties public stakeholders face in controlling diffuse urbanization and the plans that emerged to manage it. Informality has mainly been examined in Southern cities, with studies typically criticising the institutional weakness that leads to inadequate planning implementation. By contrast, informal urban processes are rarely investigated in the North, despite their frequency and magnitude. We compare the strengths and weaknesses of the planning methods, paying special attention to the planning of public facilities, which trigger controversial negotiations between private and public actors. Because public actors often have trouble developing effective financial plans, we examine the original funding solutions proposed by the private sector and associations of urban residents.