A big city on a human scale, Grenoble has been an outsider in the world of French local politics since the 1960s. A coalition of Greens, the Left, and citizen groups came to power in 2014. The Alpine city is today a laboratory for municipal ecology and its mayor, Éric Piolle, wants a second mandate. In the run-up to municipal elections in March, Quentin Ariès looks at the track record of “ecology in one city”. Between difficulties with different levels of government, the classic trap of moving rather than fixing problems, and persistent security issues, the challenges are many. That said, the energy unleashed in five years of city government has drawn support from across the progressive spectrum. With weeks to go, Grenoble is looking to the future, hoping to keep its place among green cities.