This document presents the system of surveys and indicators, in use since 1987 which allows France Telecom to monitor customers on a permanent basis. It then goes on to explain how this set-up mobilises and stimulates operational units. It also describes the role and the missions of a permanent group of experts, which advises on the conception, production and diffusion of the programmes results. The role and missions of experts are illustrated by nearly a dozen examples of operations. The conclusion brings out the main items of our review of ten years of customer monitoring, together with the facilitys prospects for future development.