This paper compares the socioeconomic potential of heating systems that could be developed in the Lyon urban area (France). The district heating (DH) systems investigated in this paper use low-carbon heat sources: large-scale heat pumps (LSHP) or nuclear combined heat and power plants (NCHP). They are compared with electric boilers and central gas boilers in terms of greenhouse gas emissions and heating costs. The heating systems are dimensioned to supply the projected 2030 heat loads for two different land surface areas (extensive and compact). The key input data is the empirical residential and tertiary heat demand per square kilometre for 2015, extrapolated to 2030 to account for the potential decrease in the heat demand (energy-efficient buildings). Given the assumptions made in this paper, the heating system that obtains the best balance between CO2 emissions and heating cost relies on an NCHP located about 30 km from Lyon. Cases in which the heat has to be transported over longer distances are considered, hence providing insights for metropolitan areas with similar size and density as the Lyon area. Implications for stakeholders and policy makers are discussed, so that to optimize future French energy systems through the most efficient use of available technologies.