Paris, France — September 14, 2005 — Dassault Systèmes (DS) (Nasdaq: DASTY; Euronext Paris: #13065, DSY.PA) today announced that it will adopt the new Microsoft .NET-based application customization solution, Visual Studio Tools for Applications (VSTA), within its V5 PLM (Product Lifecyle Management) solutions.

Support for VSTA is targeted at DS customers who have adopted .NET technologies. VSTA integration will help these customers to extend V5 solution capabilities in line with their specific needs by offering a significantly advanced environment to capture, store, enrich and reuse their in-house best practices and knowledge. Furthermore, because VSTA will run alongside existing VBA code, older and newer implementations of the V5 PLM solution will work side-by-side.

“Our customers have been capitalizing key, in-house best practices for years,” said Florence Hu-Aubigny, director, Research & Development, Open Architecture for Dassault Systèmes. “By adopting VSTA, we want to offer them the power to optimize the use of their corporate knowledge easily and cost-effectively within their V5 PLM environment.”

“Dassault Systèmes is a strategic partner and we are delighted to offer value to their customer-base by providing next generation application customization technologies,” said KD Hallman, general manager of Visual Studio Tools for Applications at Microsoft Corp. “By integrating VSTA with its V5 PLM solution set, Dassault Systèmes is meeting the needs of customers who have adopted .NET. These customers now have an optimized and managed code programming environment that takes application customization to the next level.”

About Dassault Systèmes

As world leader in 3D and PLM (Product Lifecycle Management) solutions, the Dassault Systèmes group brings value to more than 80,000 customers in 80 countries. A pioneer in the 3D software market since 1981, Dassault Systèmes develops and markets PLM application software and services that support industrial processes and provide a 3D vision of the entire life cycle of products from conception to maintenance. Its offering includes integrated PLM solutions for product development (CATIA®, DELMIA®, ENOVIA®, SMARTEAM®), mainstream 3D design tools (SolidWorks®), and 3D components (Spatial/ACIS®). Dassault Systèmes is listed on the Nasdaq (DASTY) and Euronext Paris (#13065, DSY.PA) stock exchanges. For more information, visit http://www.3ds.com