Written expression keeps a good position in French instruction, first and foremost because it is supposed to synthetize all other learning in this subject. It enables to control the mastery of the language and to convey to the pupil the rules of the different kind of texts. Evaluation of written productions allows teachers to assess the acquisition by pupils of these notions, and let them progress. Yet, this exercise also calls upon pupil's imagination, his writing representations, and his capability of creativity. Teachers seem to think very little about this side of pupil's written productions, because either of a lack of interest, either of its rejection, or admission of their inability in front of this largely unknown aspect of the pupil's individual. Therefore, the risk will be to unintentionally develop negative mental representations of writing among pupils.