Steel industry has been engaged for a very long time in a downsizing process which has deeply transformed social and industrial relations, work and employment management. Once, these industry was owned and managed by big national groups (sometimes public) and employed a lot of workers at different levels of qualification. Now, a large movement of concentration leads to the emergence of transnational leader. Steel industry has become more and more a footloose industry, with high technological level. After several downsizing operations, firms must adopt now more flexible strategies which integrate the aging of workforce (with the retirement of baby- boom generation), and the question of transmission of skills. The age management represents now the main way – and the cheapest one in the short term– to reduce and optimize the firm workforce, but also a crucial issue for the preservation of knowledge and skills, required by the activity. In these conditions, how do firms manage the new context of financial and economic crisis? What are the consequences on labour and industrial relations, and work organisation in two important plants belonging to two international leaders? We intend to discuss the hypothesis of the convergence of firms strategy and employment system. We will wonder if, and how, historical background and the nature of labour market in which firms are embedded, influence the downsizing strategy and the age management of firms. We will focus our comparative analysis on two steel plants, localised in France and in Japan. We will examine changes that have occurred in labour and industrial relations and human resource development in two steel industry plants after the 1980s, in Japan and in France. The paper presents the intermediate results of a comparative research on new dynamics of labour markets in France and in Japan . It has been led both by Japanese and French researchers which used statistical databases on Japanese and French Steel industry and qualitative methodology (semi-directive interviews).