Telecom Bretagne is a French graduate engineering school in Information and Communication Technology. One of our ambitions is to train globally competitive technical managers able to cope with complex projects. To this end, we developed project based learning where students are in a practical situation close to their future career as an engineer. In this paper, we describe the project organisation and focus on the interactions between stakeholders (large student groups, customer, various experts, communications coach and methodology supervisors). Students have to perform a techno-economical study with a great freedom as to their team organisation. Students must discover the specific role of the stakeholders and must adjust the communication level to each interlocutor. Experts can be requested by the students to help them with technical matters. The methodology supervisors check if students' methods are efficient, they point out dysfunctions and can provoke unexpected events. A communications coach can be requested by students to help in conflict management within the team or with the stakeholders. In order to quantitatively analyse the students' progress in stakeholders' interactions, a self assessment questionnaire was proposed before and after the course. This questionnaire covered interpersonal skills (teamwork, communication) and personal skills (adaptation to change, stress resistance). The students' assessment shows a significant evolution of their management skills and their perception of complexity. Project organisation with many stakeholders and large student groups brings opportunities to illustrate complex situations. In the future, we aim to improve the experiment and analyse feedback aver a longer period.