Résumé en anglais

In this paper we prove the existence of general equilibrium with transaction costs generalizing Hahn's (Review of Economic Studies, 1973, 40, 449-461) model by introducing producers and nonconvexities (in particular we allow for increasing returns in transaction sets). We also recover any exchange economy as a special case and this allows us to analyze the effects of small frictions on bid-ask prices, consumption vectors and utilities. We prove that, generically, the induced perturbations are of the same order as the frictions.