The initiatives of conservation and valorisation of industrial heritage are particularly significant in the Nord-Pas-de-Calais region of Northern France, where key sectors of industry have developed and many disappeared : mines, steelmills, textiles, food and agricultural industries, chemistry, metal works and many others. The authors show how these initiatives represent different types of collective mobilisation, and how they put a light, at the local and regional level, on the relationships between industrial identities and local and regional policies of conservation. After a period of local initiatives, the 1990’s mark a turn : first there is a new trend in regional politics which intends to associate, inside Northern Europe, sustainable development with the valorisation of industrial heritage and collective memory; and second one notes a series of initiatives due to industrial firms which are still in full activity.