This work is the first study of adoption of GM crops by French farmers. The GM crop technology case was a fertile field for the study of technology adoption but existing literature mainly focuses on studies of these issues in USA, Africa and Asia. In France, main production area of maize in Europe, the agricultural sector is very atypical compared to the agricultural sector investigated in the existing literature on the GMO adoption. By a study of the GM crop adoption in the French context and within the main production area, the south-west region of France, this study reveals 4 determinant factors that shape the choice of GM or NGM maize cropping. Some of the factors pointed by this study are in line with the existing literature on technology adoption and output uncertainty and input uncertainty (uncertainty on the expected marginal benefits and costs to sustain the new technology). Other factors identified under the atypical French agriculture sector distinctive features are particularly novel. These new factors are linked to the implementation of the UE regulation on GM/NGM coexistence in the context of small fragmented farms (need of coordination between farmers to prevent GM dispersal) and importance of the market outlets proximity to federate farmers. These novel results pinpoint that in the French context there is a need of both vertical coordination (farmers with the operators downstream the supply chain as the outlet industrial) and horizontal coordination (among farmers in neighbourhood situation) to foster the technology adoption in such industry context.