The paper deals with the French morphological prefixation pattern [non-N] (non-qualification ‘non-qualification’, non-Italien ‘non-Italian’ and non-ville ‘non-city’). It discusses the form/meaning asymmetry displayed by this pattern and its compositionality. It is shown that the general pattern [non-N] actually corresponds to three distinct subconstructions, i.e. distinct form/meaning pairings. Although pragmatic factors may be seen as presenting a challenge to the compositionality of these constructions, it is argued that [non-N]s must be seen as compositional as long as compositionality is defined not only in terms of truth-conditional semantics, but also of pragmatics.