national audience This communication looks at the links between public expenditure and spatial distribution of activities. The focus is on regional localisation models. The first part is devoted to the construction of a regional equilibrium model based on that of Krugman, with public expenditure. Public capital is generated through a tax levied on domestic income. It is distributed exogenously between two regions. It is assumed that public capital has an impact on the productivity of local enterprises. The introduction of a public sector changes the conditions for equilibrium. The second part deals with the conditions of equilibrium and the distribution of industrial activities according to the spatial distribution of public capital. Finally, the sensitivity of the balances to the various parameters (transport cost, spatial distribution of public capital and preference for variety) has been analysed.