En considérant les problèmes communs aux pays en développement, tels que la rareté des ressources, les inégalités sociales, les problèmes dans les infrastructures et les institutions existantes, entre autres, on voit une vaste zone à explorer, encore un lieu de recherche à fort potentiel de transformation sociale.Cette recherche se justifie alors de ces préoccupations avec le contexte urbain des pays en développement et les initiatives des nouvelles initiatives de transformation, à travers du développement des micro-pratiques par les organisations de la société civile.L'objectif global de cette recherche concerne la compréhension du processus d'institutionnalisation de nouvelles pratiques de transformation des zones urbaines dans les pays en développement.Nous avons cherché tout au long de cette recherche à compléter l'objectif proposé concernant la compréhension de nouveaux moyens de transformation de l'espace urbain des pays en développement comme un processus non linéaire et complexe d'institutionnalisation et ainsi certaines contributions théoriques et empiriques ont été développées.L'importance de cette étude implique directement le problème qui l’a motivé, à savoir, les caractéristiques du contexte urbain dans les pays en développement. Cette étude a exposé une nouvelle façon de comprendre un processus d'institutionnalisation complexe, non linéaire et non déterministe, par le biais des micro-pratiques urbaines développées et mises en œuvre par les organisations de la société civile et en collaboration. / Considering issues regarding developing countries as the resource scarcity or social inequalities, infrastructural problems, and in vogue institutions, among others, it is recognizes that there is a wide open field to be explored and it is also a big locus of research with high social transformation potential. Thus in order to understand such problematics and the possibilities of transformation, new approaches are needed, as well as new organizational forms and new mechanisms to be engendered to address such changes, through the development of new practices, different from the traditional ones already practiced in developed countries. Thus considering the developing country scenario, there are huge differences and needs to focus initiatives and practices, according to the specific characteristics of such environment. It is not possible to consider with the same analytical lens, theories and tools used to understand the institutional context in developed countries. Although it is important to regard that both contexts present problems, but the nature and type of problems are very diverse. In this way it is possible to understand that it is in the urban scenario in developing countries that new practices are being developed to transform it somehow, being alternative forms to public r private initiatives (major social responsibility actions). The main aim of this research is thus to understand new transformation practices of the urban space in developing countries as a complex and nonlinear institutionalization process. In order to achieve this aim, two theoretical streams were explored that are neoinstitutional theory and more specifically institutionalization approaches. And the second theoretical approach is the activity theory, inside the spectrum of practice approaches, it is used in this research as a theoretical and analytical tool to embrace the growing complexity of the institutionalization processes as this of the urban space transformation through the development of micro practices. In order to surpass traditional institutionalization frameworks that considers the process as linear and deterministic, it is also possible to consider that there is no existing general framework in literature that guides researchers to a deep understanding of all the intrinsic complexity in institutionalization processes and its different elements. In this context, the aim of this research is to develop a more structured theoretic and analytic framework able to encompass all the elements, collectivity, non-linearity and complexity of the institutionalization process with the presentation of the activity system. Moreover, the concept of micro urban practices is developed in this research in order to achieve and specify the empiric field. This concept specifies activities developed with little resources and low cost, and deployed by civil society agents in a collaborative way in search for transformation of a specific urban space or even for the transformation of people’s engagement with the city and the space they live in. Finally, a few contributions could be developed in this research. The first one considers the deployment of the activity theory as a theoretical and analytical tool to encompass the inherent complexity of the institutionalization process that were not yet explored in the literature (until the moment). Another contribution concerns the innovative character of the studied organizations. This research is composed of two case studies of civil society and bottom up organizations that are focused in solving structural problems in Brazil through the development of micro practices.