An inner structure for a nacelle for an aircraft turbofan includes a plurality of active and passive movable portions. Each active movable portion can drive adjacent passive movable portions such that the inner structure has a nominal first position, a second position and a third position. In the second position, the active movable portions project beyond by the passive movable portions toward the outside of the inner structure after the active mobile portions have driven the passive mobile portions. In the third position, the active movable portions project beyond the passive movable portions toward the inside of the inner structure after the active mobile portions have driven the passive mobile portions. The present disclosure also relates to a nacelle having an outer structure and such an inner structure.