The various assessments of the effects of a liberalization of world sugar markets are inconsistent with each other. One cause seems to be the modeling of the EU supply response. We investigate three possible linkages between sugar production under quota and the out-of-quota or "C" sugar supply: i/ the existence of fixed costs covered by the in-quota sugar; ii / the "overshooting" behavior as prevention against poor yields; iii/ the production of C sugar as "reference building" in view of expected reforms. Modeling these effects results in the introduction of an implicit crosssubsidy between in-quota sugar and C sugar. The resulting specification is included in a detailed model of the EU agricultural sector so as to account for intersectoral linkages. We simulate the effects of the 2005 reform of the sugar sector and the effects of a ban on sugar export subsidies.