In the Traité des systèmes, Condillac analyses a plurality of systematic metaphysical doctrines, specifically, those of Spinoza, Malebranche and Leibniz. Commentators have mainly interpreted this plurality as a way for Condillac to illustrate his criticisms and to raise doubts about the main contemporary systems while using the same criteria for interpretation. However, I note that his analytic tools differ according to which philosopher or philosophical system he analyses. This paper focuses on the criticism of Leibniz’s system, and aims to show that Condillac operated from subsequent reconstructions. In order to raise criticisms against the Leibnizian system, Condillac gave it an architectonic structure that is borrowed mainly from Wolff.