In the Marshallian tradition of industrial districts, alongside theories of regional systems(Cooke, 2001), national innovation systems (Lundvall, 1992), local productive systems(Courlet & Soulage, 1994) or innovative environments (Camagni & Maillat, 2006), thecluster concept is usually treated in its spatial dimension, considering quite correctly thatgeographic proximity between firms constitutes a real factor in the diffusion of informationand knowledge (Porter, 1998). (...)