Actual ways of financing social expenditures through payroll taxes in France is often considered as exerting adverse economic and social effects. Alternate ways of financing are proposed such as VAT, income tax, investment tax, ... This article deals with the economic effects of such tax bases - on capital formation, inflation, activity level, employment, competitivness, and with the social effects - on national and household income distributions. The use of a proportional tax on household income is advocated. This way of financing is optimal both on equity and efficiency grounds but can also play a decisive role in slowing down the rate of growth of social expenditures.On accuse souvent les modalités existantes de financement des dépenses ...