Through its Climate Plan, the City of Paris is making energy control one of the key issues of its environmental policy. It has undertaken with its partners to reduce greenhouse gas emissions and energy consumption in its area by 25% between now and 2020. The Climate Plan also aims to increase the share of renewable energy in the city’s energy consumption to 25%. The District Cooling System of Climespace is the largest in Europe, with a network of more than 140 km in length and 325 MW of installed cooling capacity serving nearly 500 customers. The cooling energy produced is used, for example, for the air conditioning of the Louvre Museum, preserving the works of art and ensuring the comfort of the millions of people who visit the museum each year. Since the end of the 1990’s, Climespace has deployed a strategy based on energy efficiency. The construction of power plants cooled by the water from the River Seine, the use of renewable cold sources and fundamental changes in both the management and the operation of the facilities have enabled Climespace to substantially improve its performance between 2002 and 2010.