Since their creation in 1960, national parks have been heralded by France as the most iconic of its conservation territories. Coming as a late chapter to intertwined histories of state forestry and quasi-colonial rule (with six parks out of ten including afforested mountainous areas, and three locations in ultramarine regions), they have yet for these reasons been increasingly perceived in political circles as ‘failed territorial transplants’, leading eventually to their reform in 2006. A charter aimed at territorializing the ‘ecological solidarity’ between core and buffer areas is now mandatory for every national park, with the opportunity for municipalities included in the surrounding ‘optimal membership area’ to join or leave the partnership on a triennial basis. What I wish to address in this talk are the potential outcomes of this innovative –of not ambiguous- process for the future of state-backed conservation practices in France. Starting with an empirical analysis of the patterns of refusals (~100 out of 420 municipalities) collected by late 2015, I will demonstrate that the oppositions should not be seen as mere rebuttals of ‘ecological solidarity’, but draw on more complex blends of alternative ‘opportunities’ and heritages: the disproportionate influence of ski and seaside resort economies being one key dimension, the targeting of parks as generic embodiments of the injustices brought by the central State being another – aligned or not with the former. By fostering dynamic conservation territories and translating participatory imperatives into an expanded role for local municipal councils, the reform could be critiqued as breeding greater illegibility and clientelism. Focussing on park staff’s planning practices and perspectives, I will show they tend nevertheless to embrace a more optimistic understanding, validating somehow what might be considered as a radical shift for the socionatures of French national parks.