Abstract: Nowadays many software products are made up of millions of lines of code. Moreover, they are subject to a continuous evolution. These products are often based on component technology such as COM, EJB or Corba. Understanding and controlling the evolution of such complex software products is a difficult task, especially if undertaken at the code level. It is thus necessary to reason at a higher level of abstraction, i.e. the software architecture. This article reports on an industrial experience. The goal was to answer Dassault Syst?mes' needs by using a software architecture approach. This company maintains and develops a huge software called CATIA. In this article, we show how the architecture of CATIA can be described by the use of multiple, concurrent architectural views. This allows both to separately address the concerns of the various stakeholders of the architecture and to improve the communication between these different stakeholders.