The purpose of this paper is to analyse the influence of spatial externalities related to the location of firms on their innovation performance. We try to deepen the question of the Marshall/Jacobs dichotomy by taking into account the complexity of the different types of environment in which a firm could be located, as notably we observe that both types of externalities are encountered in a same geographically delimited area. The originality of our study also lies in considering a larger definition of the firm that is not reduced to just the head office, with the aim to better evaluate the impact of spatial externalities on innovation. We use a dataset on French industrial firms (Community Innovation Survey, CIS8) and different indicators to evaluate the specialisation and/or diversification of all the employment zones in France. The results tend to show that firms' geographic environment does not have the same effects on the probability to innovate and on innovation intensity and that the effects also vary depending on the firm's organizational structure. The diversification model tends to reveal the stimulating importance of the“Jacobian” diversity on firms' decision to engage in innovation and its negative effect on their innovation intensity. The specialization model shows that being located in the specialized zones has, on the contrary, a more positive influence on the decision to innovate and reinforces innovation intensity. Finally, the dual model confirms theses results in emphasizing the combined effects of specialization and diversification on innovation.