A bypass turbofan engine with a nacelle comprising a fan case and a thrust-reversal system. The fan case comprises an exterior wall, and the reversal system comprises a slider having an upstream frame, a downstream frame and a plurality of spars fixed between the upstream frame and the downstream frame, in which the slider is able to move between a forward position and a retracted position. The fan case comprises, at a rear edge of its exterior wall, a support. Each support comprises, for each spar, a shoe fixed to the exterior wall and positioned radially about the spar, and a skirt secured to the shoes and extending the rear edge, in which, in a forward position, the skirt bears around the downstream frame, and in which in a forward/retracted/intermediate position, the shoes are distant from the spars from the upstream frame.