It is possible to associate a CO2 content with each macroeconomic aggregate (production and imports on the supply side; consumption, investment and exports on the demand side), relying directly on the central framework of the national accounts. In 2005, CO2 emissions caused by economic activity on the French territory came to just over 400 million tonnes (6.7 tonnes per year per inhabitant). This is 1.3% of worldwide emissions, for a country whose economy represents 3% of world GDP and which has 1% of the world population. A third of these emissions come from the combustion of hydrocarbons (petrol, domestic fuel, gas) used by households for travel and heating. Two-thirds are emitted by the national productive system. However, CO2 emissions are also produced outside France due to our imports; they are actually 20% higher than the emissions from our own productive system. Conversely, foreign demand causes part of the CO2 emitted by our productive system via exports, as well as part of the CO2 related to our imports (since we import certain products in order to process them and, ultimately, satisfy foreign demand). Once all calculations are made, the CO2 emissions caused by French domestic demand come to almost 550 million tonnes (9.0 tonnes per year per inhabitant), 40% of which is emitted on foreign soil. Three-quarters of these emissions are produced by household consumption expenditure, mainly on housing, transport and food; 10% are produced by general government consumer expenditure, and 15% by investment. The quantity of CO2 generated by household consumption clearly rises with the standard of living: the wealthiest 20% of households generate 29% of CO2 emissions via their purchases while the most modest 20% only produce 11%. However, due to the differences in structure of their consumption baskets, the CO2 content per euro spent is lower on average for a well-off household than for a modest one.