The debate on digitalisation and changes in manufacturing has focused on the digital ‘twin/digital shadow’ dichotomy, two approaches to digital technology implementation. At the same time, the literature has paid great attention to the integration between the Industry 4.0 paradigm and lean production as well as to the different outcomes of such integration in terms of ‘augmented lean’, ‘distorted lean’ and ‘lean trap’. This paper analyses the approaches to digitalisation adopted by two German-owned manufacturing firms in Northern Italy that have implemented lean production, focusing on the factors behind this adoption and the potential consequences on working conditions and organisation. The two companies are leaders in their respective sectors (sports cars and high-tech air conditioners), are inspired by lean principles and adhere to the I4.0 paradigm, to which the literature tends to refer the digital twin approach; however, the results show that in both cases a digital shadow approach predominates, even if the factors underlying this choice appear to be different. The research highlights how the implementation of a ‘digital shadow’ approach, while reducing the risks of technology substitution of jobs, can have critical implications on working conditions and, above all, can lead to a ‘lean trap’ by limiting the innovation potential of new technologies, while jeopardising the sustainability of lean itself.