This paper presents the results of an empirical study focused on the observation and analysis of an innovative design process. We have had the opportunity to observe and participate in the early phase of a new innovative project within a design office of a truck manufacturer. Our observations based on the actor-network theory highlight the importance of the various design rationales carried by the actors involved. The results of this study show the weakness and complexity of an innovative process within a highly constrained environment. We particularly show that carrying out innovation requires different viewpoints with regard to the object of the design to evolve along with the network of actors and the organisation involved. The issue of product and process integration involving knowledge transfer between actors throughout the design process is also discussed here. As a result, we highlight the importance of rethinking the interface role played by the material expert (in our case) and, in line with other works, we put forward the "interface actor" as the key network actor involved during the early development phases. To provide the network and the interface actor with a means to share information and co-operate during these informal early design phases we propose some features of a new web-based information system and the basis for a debate on the idea lifecycle management concept as a solution to the issue of innovative idea information structuring.< Réduire