On November 6, the UN Climate Change Conference (COP23) started in Bonn, Germany. Under the presidency of Fiji, for two weeks delegates from around the world are negotiating the implementation of the Paris Agreement with a focus on developing guidelines for transparency, emission reductions, provision of finance, and technology. What role do cities and regions play at COP23, and what is new compared to previous climate conferences? Lou del Bello reports from Bonn.