Experiment could see sewers heat 10 per cent of city with President Sarkozy's Elysee Palace already signed up
Minister proposes temporary carbon tax on big business in attempt to secure support from Constitutional Court
Deadlock continues over emissions targets, but reports claim gradual progress is being made on climate funding mechanisms
Official: "We should try to complete the job earlier than later"
President insists new tax on carbon emissions essential to France's development as a low-carbon economy