Abstract : This study, is articulated around the semantic and lexical analysis of the verb « changer » (to change) in the political program of 1994 of the french political party « Les Verts » : The Book of Les Verts – Dictionary of political ecology. The objective is to distinguish the various senses from the verb « changer » in this program and to understand the sense of their slogan « Changer tout » (To change all). Several questions then emerged : is this a radical political program suggested by the semantism of the verb ? Is this a particular sense of the verb « changer » in this program ? Would there be a political definition of the verb « changer » ? To answer these questions, we operated in two distinct stages : an analysis in language, starting from various dictionaries, of the verb « changer » and its quasi-synonymous in order to extract an about stable significance ; then a microsemantic analysis in context in order to check if the sense of the verb remained identical to the significance of the lexeme in language.