Abstract : Higgs bundle theory has proven to be a power tool in describing character varieties of surface group representations. However, it is difficult in general to understand geometric properties of a given representation by looking at its corresponding Higgs bundle, because the correspondence involves solving a system of PDEs. In recent work with Brian Collier and Jeremy Toulisse, we derive from Higgs bundle theory refined geometric properties of representations into a Hermitian Lie group of rank 2 with maximal Toledo invariant. The key fact is that Higgs bundles provide us with the existence of a minimal surface in a pseudo-Riemannian G-homogeneous space, whose geometry is easier to study than that of a Riemannian symmetric space of a Lie group