The goal of this talk is well pose and solve the following semi-classical inverse problem: The potential V(x) in the Schrödinger operator can be recovered, under some weak genericity assumptions, from the spectrum of modulo . This work is a simplified version of a Seismology problem studied by Colin de Verdiere, M. Campillo and all. We will discuss about that motivation and we show the main ideas of a constructive proof by the previous problem.