ATG Strengthens Presence in France with New Partnership

Agreement with Sopra Group Teams E-commerce and SI leaders to Deliver World Class Solutions

READING, United Kingdom & PARIS, Jun 28, 2006 -- ATG (Art Technology Group, Inc., NASDAQ: ARTG), has today announced a new partnership agreement that strengthens the company`s presence in the French marketplace. ATG`s licensed and on demand technology powers e-commerce sites and corresponding e-marketing and customer service for the world`s most customer-centric enterprises, and it has teamed up with one of the largest leading IT systems integration and consulting businesses in France, the Sopra Group, to deliver e-commerce and customer experience solutions and services to the French market. It is anticipated the Sopra Group will extend this collaboration to its other European operations in the UK and Spain.

Peter Ford, ATG Alliances Director for Europe, Middle East and Africa said of the agreement, "This is a significant partnership for us as the Sopra Group has extensive capabilities that will help us provide both our existing customers such as France Telecom, and our new customers, with world class e-commerce solutions. An increasing number of French companies are realising the business value of deepening their customer interaction across multiple channels. Extending the value of their conventional e-business solutions, ATG is delivering additional benefit by providing solutions across commerce, marketing and customer care, including integration with Call Centre operations. The results show an exceptional return on investment."

Francois Rabasse, Deputy Divisional Manager for Sopra Group said, "We see this agreement as strategic to our business. ATG has long been recognised as a leader in its field. The alignment of their business towards e-commerce and customer experience management is something we see reflected in the requirements of our customers, and therefore we are very pleased to have signed this agreement. The goal is to add value to our offerings that we provide to our larger customers in this area."

About ATG
ATG (Art Technology Group, Inc., NASDAQ: ARTG) makes the software that the world`s most customer-conscious companies use to create a more relevant and consistent customer experience, throughout the marketing, commerce, and service lifecycle, and across the Web, e-mail, call center, and mobile channels. Offering an alternative to the traditional silo-based approach to customer-facing applications, ATG Wisdom(TM) is the company`s strategy for delivering a seamless, more compelling, and mutually valuable experience to each customer and segment. The company fulfills this strategy by providing fully integrated best-of-breed product suites installed on-premise or delivered on-demand. ATG`s solutions power over 600 major brands, including A&E; Networks, Airbus, American Airlines, American Eagle Outfitters, Best Buy, Boeing, Cingular Wireless, DirecTV, France Telecom, Friends Provident, Hewlett-Packard, Hotels.com, Hyatt Hotels, HSBC, InterContinental Hotels Group, Kingfisher, Louis Vuitton, Merrill Lynch, Neiman Marcus, Philips, Procter & Gamble, Symantec, T-Mobile, Target, USAA, US Army, US Navy, Warner Music, and Wells Fargo. The company is headquartered in Cambridge, Massachusetts, with additional locations throughout North America, Europe, and Asia. For more information about ATG, please visit www.atg.com.

About Sopra Group
A major player in consultancy and IT services in Western Europe. With a total workforce of 9,300, Sopra Group provides a large spectrum of services required by companies to further develop their business improving their organisations and their information systems. Sopra Group offering is global from strategic analyses upstream of projects to final implementation of major systems integration and to outsourced management of larger business critical applications.

Sopra Group has a solid know-how in specialization markets such as Banking & Insurance or Telecommunications & Medias.

Through its subsidiary Axway, the Group pursues the worldwide deployment of its activities in both application integration and business processes implementation, with a unique range of BPM and B2B solutions. More information at www.sopragroup.com

(C) 2006 Art Technology Group, Inc. ATG and Art Technology Group are registered trademarks, and ATG Wisdom is a trademark of Art Technology Group, Inc. All other product names, service marks, and trademarks mentioned herein are trademarks of their respective owners.

This press release contains forward-looking statements for purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. These statements involve known and unknown risks and uncertainties that may cause ATG`s actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by such forward-looking statements. Important risk factors affecting ATG`s business generally may be found in its periodic reports and registration statements filed with the Securities and Exchange Commission at www.sec.gov . Risk factors related to the subject matter of this press release include the possibility that the ATG product deployment will not be successful, on time or significantly enhance the user`s Internet experience or will not increase customer revenue across brands; that those customers leveraging ATG will not have the opportunity to increase revenue and decrease future costs; the need to adapt to rapid changes so products do not become obsolete; the possibility of errors in ATG`s software products; the possibility that the solution will not make customer implementations faster or more flexible or permit the customer to meet its customer-facing or infrastructure requirements; that the ATG product will not continue to be integrated with third party applications servers or will not support all Web services enabled systems; that ATG`s product strategy may change in the future; and the risks and costs of intellectual property litigation. ATG undertakes no obligation to update any of the forward-looking statements after the date of this press release.

ATG
Tucker Walsh, 617-386-1159
twalsh@atg.com