Based on a seminal policy paper (Foray et al., 2009), the Smart Specialisation Strategies (S3) approach was integrated into the reformed cohesion policy of the European Union for 2014-20. This large-scale European experience provides a unique case study of a new type of industrial policy particularly oriented towards the modernisation of industrial sectors. In this paper, we briefly review the fundamentals of the S3 approach. We identify and discuss the main properties of S3 that make it particularly suited to the problem of sectoral modernisation in the context of a mature economy. In the final part, we describe the designing of this policy, which represents a crucial point: whilst the objective of modernising traditional sectors is not in itself anything new, the way of proceeding within the S3 framework is relatively new and innovative.