Studies in the field of sociology of innovation and economics of technical change have shown that technologies and their markets are highly intermingled. If we accept that technologies can shape the market, it leads to paying attention to how technologies are designed and developed. Indeed, the characteristics of technologies influence the nature of the competition (network externalities, increasing returns to adoption,...). The importance of co-operative R&D agreements is mostly analysed in terms of successes and failures or in terms of reduction of transaction costs. But, does the mode of development of technics have effects on the characteristics of the technical objects ? The impact of the mode of development of the technics on the characteristics of technics is still mysterious. Could it be that one of the determinants of the characteristics of technologies is the way in which technological development is organised ? The aim of this paper is to present some hypotheses about the consequence of R&D co-operation on the characteristics of the technical object in an actor network perspective.Thanks to an ethnographic study of the mode of coordination of a Eureka project, the role of technics as a mechanism of coordination is highlighted. Thus, technical choices can be analysed as the result of the identity of the actors of the cooperation, of their mutual trust and of the form of cooperation. Hence, the form and the nature of the technical object, which shapes the market, are the result of the organisation of its development.