In Descartes, the idea of infinity appears ambiguous: it is at the same time the idea of the foundation that goes beyond rationality, and the idea that is integrated into rationality to demonstrate this foundation. Thus, at the heart of the divine infinite, a tension appears: Descartes has associated in the same name of infinite a metaphysical determination and a non-metaphysical determination of God. To show this, we will try to read Cartesian metaphysics through the prism of Duns Scotus and Emmanuel Levinas.