?Métabolisme Urbain de Paris? (http://metabolisme.paris.fr/) is a web data visualization developed in 2014 by Elioth for the City of Paris, regularly updated with new material and improved usability features. The aim of this visualization is to popularize the concept of urban metabolism for policymakers, project leaders and citizens, by showing how energy, material and water flows are set in motion to support the life of a city : what is the annual amount of electricity, gas, oil, heat, consumer goods, food, and water coming in and out of the city? Does the city export more goods than waste? How dependent is the city from energy imports? What are the most important issues and flows to give priority to ? Designed and implemented for the City of Paris ?Urban Metabolism Optimization? policy, the website presents more than 40 concrete and local optimization solutions of these flows, depicting examples of effective and already operating solutions of the much talked about circular economy (http://metabolisme.paris.fr/#p): how could we reuse materials like granite pavements from demolitions instead of importing new ones? How is the sand of ?Paris Plages? recycled each year? How could waste be turned into energy or reusable materials?