The purpose of this paper is to assess the effects of inter-municipal fiscal cooperation on municipal public spending, based on the French experience. We estimate a model of municipal spending choice using panel data and spatial econometrics for municipalities over the period 1994-2003. We provide two main results. First, inter-municipal cooperation has no significant impact on the level of municipal public spending, which suggests that cooperation does not achieve its goal of reducing municipal spending by the sharing of local responsibilities. Second, there are no spending interactions between municipalities belonging to the same inter-municipal community. This is in line with the goal assigned to cooperation in terms of internalization of spatial externalities. However, our results show that benefit spillovers remain highly significant outside inter-municipal communities, suggesting that inter-municipal communities remain too small.