A rescue excavation has unearthed the remains of a bridge crossing the Moselle River at Dieulouard (Meurthe-et-Moselle, France). This constitutes one of the rare examples of non-religious monumental architecture from the Carolingian period in France. The present archaeometrical study, conducted on a set of architectural iron fastenings, provides an opportunity to examine the modalities through which early medieval building yards acquired ferrous materials. Located within the vicinity of active ironmaking zones, a hypothesis was subsequently put forward that the iron supply was provided by a local market. The results nevertheless highlight a more complex acquisition strategy than expected, relying at least partially on metal salvaging. This study therefore stimulates current discussions of the importance of recycling in the Carolingian economy, and of the value attributed to material and its transformation