In the contemporary context of the Anthropocene, Rights of Nature and legal personhood of natural entities are often promoted as potential solutions to avoid ecological crises. However, a critical approach highlights the instrumentalisation of these concepts within the framework of relations of power. The development of the discourse surrounding the Rights of Nature and legal personhood in Europe gives rise to inquiries regarding the potential instrumentalization of these concepts. This approach represents a profound departure from the legal frameworks and relationships with nature that currently predominate in Europe.

This thesis explores this paradigm shift, focusing on the introduction of the legal personhood of a transboundary watercourse into the political agenda by actors peripheral to the decision-making process and water governance system. The research question that guides this study is as follows: “In a transboundary context, characterized by different institutional and legal frameworks, how do actors and coalitions of actors reappropriate the concept of legal personhood and to what extent do they reopen the governance of a river?”. This present study is grounded in three theoretical frameworks: political ecology, analysis of policy process and political geography.

The introduction commences with a synopsis of numerous cases in which the legal personhood of aquatic ecosystems and rivers has been recognised and implemented. This is followed by an exposition of the theoretical framework of the study. Chapter 2 provides an analysis of the cases of the Whanganui, Atrato and Turag Rivers and the Mar Menor lagoon, highlighting the variables that explain the legal evolution. These variables are then used to discuss the conditions of emergence of the discourse on the legal personhood of the Rhône transboundary river. Chapter 3 provides an in-depth analysis of the strategies employed by the various actors involved in this discourse. Finally, Chapter 4 explores the imaginaries revealed through the concept of legal personhood, exhibiting the interweaving of different visions of the world and the river, ranging from extractivism to democracy and ecocentrism.

The discourse surrounding the legal personhood of the Rhône River has not yet been performative. However, ID-Eau and CIPEL are employing a variety of participatory tools, including petitions, citizens' conventions and public meetings, which demonstrate the bottom-up nature of these initiatives. These initiatives raise questions about the governance of the river, regarded as a socio-ecological object, through the lens of power relations. The construction of a collective problem, for which legal personhood would be the solution, deserves to be consolidated. Should the recognition of the legal personhood of the Rhône river prove to be a societal demand, water governance should integrate this concern. In the context of a change or reform of decision-making processes, involving citizens in a different way in decision-making would make it possible to move from predominantly technical and administrative governance to predominantly political one. It is conceivable that this could renew the democratic foundations.