Primary energy sources
District heating network ? District heating

Until the onset of the energy crisis, district heating in France was supplied by boiler plants burning conventional fuels, apart from a few rare cases of household waste incineration plants or combined heat and power plants.

We've seen the development of plants powered by geothermal sources, household waste, industrial waste and solar energy.

As far as the use of nuclear energy is concerned, it seems to have been limited to a few tests.