"SINFONIA utilizes EU funds to bolster public/private resources and provide European added value to already committed district refurbishment master plans of two middle sized European cities (Bolzano, Italy and Innsbruck, Austria), the targeted performances of which combine three key features thanks to industry involvement: i) unique cooperation between the cities belonging to the same climate zone in Europe, but working under different regulatory regimes (Austria, Italy), ii) single collective ambition in reducing energy needs to meet human activity requirements, and the related CO2 emissions (40 to 50 % primary energy savings per district, 20 % increase of the share of renewable energy uses), iii) several innovations in network infrastructures and technology interfaces that enable smarter use of energy at district level, a stepping stone to guarantee a reliable and progressive transition toward low carbon cities. Moreover, SINFONIA aims at validating a comprehensive, interdisciplinary, refurbished city district model where the potential for scalability and replication by middle-sized European cities is built and validated during demonstration, based on energy technologies deployed by the two pioneer cities. This model emphasizes the role of an innovative integrated energy system approach, linking energy efficiency and CO2 abatement. The model robustness is reinforced by five “early adopter” cities which are full project partners in Cyprus (Pafos), France (La Rochelle), Germany (Rosenheim), Spain (Sevilla) and Sweden (Borås). They use the tested scalability and replication rules to reinforce their impacts on the five future city district refurbishment processes, thus showing that district renovation can be prepared under different sizes, climate and regulatory conditions (Scandinavia, Central Europe, Atlantic, and Mediterranean). A robust exploitation plan with a complete European perspective is then designed involving replication cluster cities and industry."