Recent research in music psychology and computational analysis now allows to take a scientific look at the musical expression in interpretation. This paradoxical cohabitation of the performer’s freedom and empirical methods implies to consider the complexity and the multiple possibilities of interpretation through the study of the recordings. Based on Juslin and Laukka’s research (2003) on the expression of vocal emotions, this article studies the interpretation of “Les Hiboux” (“The Owls”) by Baudelaire-Vierne in the recording of Delunsch-Kerdoncuff. The score analysis and the interpretation analysis are brought together by considering the poem as an element as important as the musical notation for a proper understanding of expression.