This paper assesses the consequences of two reforms of the French indirect taxation system: a VAT harmonization which is close to initial EC proposals and a carbon tax which aims at decreasing the emissions of carbon dioxide. We simulate the effects of tax reforms using estimates of a model of household expenditure behaviour. Estimation is obtained by using the property of perfect aggregation over households of the Almost Ideal demand system on pooled micro data from the 1978–1979, 1984–1985, 1989 issues of the French ‘Enquête Budgets des Familles’ combined with macro data from the Quarterly National Accounts from 1970 to 1990. Simulations are conducted using a subsample of households from the 1989 consumer survey and generate useful results about the behavioural reactions to tax changes, the impact on government revenue and the distributional effects of the reforms.