In 2006 a terrible fight pitted two steel makers, Mittal and Arcelor, against each other. Understanding the dynamic of this enormous takeover requires a historical perspective. The structure, business strategy, and corporate governance of these groups evolved over a long period of time. This article explores the conflict in the context of the history of French steel industry. An examination of Usinor, moreover, as the ancestor and creator of Arcelor, can reveal a lot about the political, social and economical influence of steel makers in French society. Understanding the conflict also calls for an analysis of how a large company could change its corporate culture. Instead of reducing corporate culture to individual or collective “values,” as Edgar Schein did some time ago, this article explores Usinor's culture as a system of representations, material elements, technologies, products and ways of doing and thinking.