This paper investigates the consequences of European markets integration, by developing a neo-keynesian model where fiscal policies affect firms' market power and employment. Stronger product market competition is shown to reduce the marginal ability of governments to improve employment through public consumption. As competition crowds out fiscal spending, the positive impact of markets integration on employment is weakened. Moreover, in a context where national goods' demand becomes 'global', the marginal benefit for each national fiscal authority of increasing public consumption is lower than the marginal benefit for the community. This result stresses one source of coordination failure within EMU.