[en] The development of the tertiary sector appears to support sustainable development since it now accounts for almost two thirds of the national economy and is responsible for low CO₂ emission levels. Between 1980 and 1997, CO₂ emissions from the tertiary sector increased by 20 % compared with a 48 % rise in the sector value added. In terms of production, CO₂ levels in the tertiary sector are low, compared with 55 % for the secondary sector (industry). However, when trade between economic activities is taken into account, there is cause to qualify the assessment. This makes it possible to ascertain emissions from the point of view of satisfying final demand for products, and to identify direct and indirect emissions in each branch of activity. Thus, when emissions from certain industrial and agricultural activities are redistributed specifically to branches of activity in the tertiary sector, CO₂ emissions in this sector account for almost one-third of total emissions. (A.L.B.)