This paper presents the current developments performed at ONERA to extend the aeroelastic adjoint method in the CFD software elsA towards an aerostructural adjoint. Because multiobjective and multipoint optimizations require an aerostructural design space, a tool for fully-flexible wings is created utilizing Python and Fortran. This structural module provides an equivalent beam model based on the CFD surface mesh of the wing, the internal structural geometry that meets the aerodynamic limit loads as well as an estimation of the wing weight. This module is integrated with the existing aeroelastic environment for adjoint-based optimization.