Timeline

Heritage classified

Key figures

Origin and history

The Bonpertuis forges, located in Apprieu in Isère, came into being in 1434, with an attested mention of their steel industry. Their history was marked by a major conversion in the 19th century under the impetus of the Gourju family, which modernized the installations in 1859. Alphonse Gourju, a renowned forge master in the Gresivaudan, installs a puddler oven and two steel cement furnaces, now considered as the last copies kept in France. These equipments, inspired by English methods (coke, rolling mills), symbolize the industrialisation of regional metallurgy.

Over the centuries, forges evolved with technical needs: after World War I, electric arc furnaces were added, diversifying production to sectors such as cutlery, automobiles or medical. The Experton family then perpetuates the metallurgical tradition until the 21st century. Despite their judicial liquidation in 2025, the forges remain an exceptional testimony of the French industrial heritage, with their cement furnace classified as a historical monument in 2003.

The historical importance of forges is also linked to their role in the local economy. In 1574 Jehan Perron, a Tullins merchant, developed a massive steel factory to meet the needs of the Italian wars. In the 19th century, the furnaces dealt with local (Brignoud) and external (Loire, Midi) fonts, illustrating the integration of forges into national industrial networks. Their architecture, like the brick oven reinforced with iron bars and surmounted by a 10-metre conical chimney, reflects the engineering of the time.

Today, although privately owned, Bonpertuis forges continue to fascinate with their state of conservation and their representativeness of technological change. Their inscription in the title of historical monuments underlines their heritage value, while their location in Apprieu, near Grenoble, makes it a key site to understand the industrial history of Isère and the Auvergne-Rhône-Alpes region.

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