Ademe gives 100 tips on its site, which it says could reduce energy consumption in the home by up to 12%.
With heating accounting for 60% of energy bills, it recommends closing curtains/shutters in the evening to reduce heat loss by up to 60%, and using a thermostat to set temperatures between 19C and 21C in the day, and 17C at night. One degree lower can save 7% on your bill.
It also advises maintaining boilers and purging radiators annually.
Switching off appliances rather than leaving them on standby can save up to 10% on bills, it adds, not including heating. Internet boxes use, on average, 150 to 300kWh a year, so switch them off too when not in use.
Led lighting, as long as it is marked A+ or A++, uses 132kWh a year compared to 375kWh for halogen bulbs.
In the kitchen, defrosting food overnight in the fridge rather than in the microwave saves electricity, while putting the lid on saucepans uses 25% less energy.
Ademe says that Eco programmes on washing machines and dishwashers really do use 40% less electricity, even though the cycle is longer. Choosing low temperatures is also good practice, as is spinning clothes at a high speed and hanging them out to dry rather than using tumble dryers.
The optimum temperature for fridges is +5C, and -18C for freezers, which use less energy the fuller they are.
Defrosting regularly and cleaning the back grille every year helps them work better.
Your choice of appliances will also make a real difference to energy consumption.
For pointers, Guide Topten is an Ademe-backed website to help choose the most efficient devices.
It lists purchase price, running costs and specifications for different brands, covering all basic home appliances, including heating and computers.
You can also search for a cheaper energy supplier using the government comparison site Energie-Info.