This article analyzes the temporal use of the (present) conditional in the negative factive constructions {ne pas savoir / ne pas se douter / ignorer que} + conditional (e.g. Ma fille ne se doutait pas que je passerais par là ‘My daughter did not suspect I would go through there’), that seems to invalidate the hypothesis according to which ulteriority is calculated from a reported enunciation. The corpus study highlights that the conditional, found in positive factive structures from Old French onwards, only appears in negative factive structures in the 17th century. We hypothesize that, on the grammaticalization path of the initial subjective use into an objective use (19th century), that construction constitutes a switch context, in which the subjective source value disappears in favour of the objective target value.