Points clés :

• This paper studies theoretically and empirically the relation between institutional quality and customs evasion.
• We develop a model interacting customs officers and importing firms behavior. We consider different cases such as collusion versus corruption and endogenous versus exogenous inspection effort.
• Emprically, in line with the general framework, we find a positive, and marginally decreasing, tariff elasticity.
• The tariff elasticity becomes negative above a given threshold. It is consistent with either a non-collusive framework or a collusive one where the custom officer knows that the probability of control is higher for higtariff products.
• Institutional quality, e.g. transparency, reduces the evasion elasticity while the ease of enforcement (differentiated products) matters only if customs officer does not collude with importing firms.

 Résumé :
Tariff receipts are important for many countries but their collection is often problematic. To analyze why and to what extent this occurs we first model customs duty evasion as an interaction between customs officers considered to be corruptible law enforcers, and importing firms. In this context, higher tariffs generally lead to greater customs duty evasion but their marginal impact is decreasing, and may turn negative above a given threshold if customs officers adapt their inspection effort endogenously. While transparency (the probability of effective control) always limits evasion, we show that ease of enforcement (e.g. ease of establishing the shipment`s true value) matters only if customs officers do not collude with importers. Our empirical analysis spans 55 importing countries over the period 2001-2010 and confirms our predictions. This lends support to the assumptions of endogenous inspection effort and widespread collusion. World Trade Organization membership is found also to limit the extent of duty evasion.

 Mots-clés : Tax Evasion | Customs Duty | Institutions | International Trade

 JEL : J13, H26, K42