We study how French exporters react to a VAT shock in a destination country. VAT shocks are by nature almost permanent, exogenous, and have no impact on marginal costs. We argue that the subsequent price reaction therefore identifies to which extent mark-up adjustments tame the impact of a macro shock on final consumption prices. We show that even a uniform increase in the VAT rate can entail non-uniform mark-up adjustments across exporters and, consequently, an important redistribution of profits both between sectors and across firms within a sector. Indeed, mark-up adjustments vary with the elasticity of demand and the market shares.