Despite increasing cooperation between French municipalities, the structure of the local public sector may not have significantly changed. Although the central government expected that this co-operation would resuit in a decrease in the combined rates of municipal and inter-municipal taxation, this very cooperation may have brought about the opposite effect. Up to now, this controversial hypothesis has never been rigorously examined. The article shows that it cannot be dismissed however. A 10% increase in the rate of inter-municipal taxation results in a reduction of only 1 % in the rate of taxation in the majority of the municipalities and can even induce an increase in rates for the smaller urban municipalities.Le développement de la coo...