Jean-Guillaume Sahuc Banque de France and EPEE, University of Evry   Banque de France, Research Division 31 rue Croix des Petits Champs Paris, 75049 France   jean-guillaume.sahuc@banque-france.fr   http://perso.wanadoo.fr/jean-guillaume.sahuc/           JEL Areas: E3 : Prices, Business Fluctuations, and Cycles: General (includes Measurement and Data) C2 : Single Equation Models; Single Variables: General