This article presents a semantic description of French denominal verbs, such as EMBARQUER, EMPOISONNER, ENDIMANCHER and ENDEUILLER. Traditionally described as parasynthetic compounds, these verbs are the result of a special type of word formation, consisting in the affixation of a prefix and suffix to a stem. Our purpose is to deal with a semantic description of this particular verb class, based on the referential and cognitive nature of de noun stem. It will be shown that the semantic classification outlined by Fradin (2003) in verbes en-SITE (EMBARQUER, ENFOURNER, ENGLUER) and V-cibles (ENCOLLER, ENFLEURER, ENGLUER), based on the cognitive figure-ground opposition is not general enough. The thesis defended here is that denominal verbes enXer instantiate a transformational process of a more abstract topological kind.