Paris’ Deputy Mayor for Environment, Célia Blauel reflected on how hosting the world’s largest climate event helped accelerate the transition to a greener city. Blauel and her team plan to use the platform of COP21 to cement the city’s legacy of innovative urban sustainability initiatives in areas such as climate adaptation, water policy, air and noise pollution, renewable energy, and increasing awareness of the need for sustainable development. But how exactly will Paris extend its legacy of green innovation, including car free days and its ambitious climate plan that will see the city reduce GHG emissions by 25% by 2020?