Even if recently the notions of citizenship and community have become buzz words of very positive connotation, significant tensions underlie any of them: between homogeneity and difference, belonging and diversity, inclusion and exclusion and, more recently, between freedom and security. Real communities are places of cooperation and mutual recognition as much as they are places of inevitable conflict, social control and exclusion. Following an ecological and contextual perspective, and a relational definition of community, concepts such as sense of community and social capital are explored. An analysis of citizen’s participation in their communities illustrates significant dimensions of participation: power, dialogue, initiative, formality, pluralism and time. The discussion considers how these dimensions might contribute to making community organizations turn into 'schools of democracy' (de Tocqueville 2000), and illustrates this potential with young migrants, as long as the diversity of diverse migrant groups is not only recognized but furthered.