The scientific knowledge and operational literature about collaborative housing is most often local oriented, that is to say built from experiences involving a group of citizens and local stakeholders. On the other hand internet is a global medium used by actors of co-housing to exchange and collaborate. Between the local and the global levels, what happens on the intermediate scales, such as the state and the regions? What is the nature of national and regional strategies, policies as regards projects or realisations in collaborative housing in European countries? Which one of these levels provides a legal framework? Are the levels of the state and the regions convergent or antagonistic in some countries? We argue that the housing issue is mostly national oriented, and that the conditions of development of co-housing is thus very dependent on the territorial structure of the state (centralized, federal, or decentralized), on the national and regional structure of housing supply, on the national and regional history of social housing. We will develop these questions in a comparative way between in Central and Western Europe, i.e. in France, Spain, Austria, and Poland. This paper aims to test comparative perspectives of research on the topic of collaborative housing.