In the frame of the socio-economic monitoring of the Bretagne-Pays-de-la-Loire high-speed line (LGV BPL), a dedicated working group has been set up to study the direct and indirect impacts of the infrastructure on the farming sector. Gathering all the concerned stakeholders, this group aims to coordinate and follow the progress of the various studies on the topic. Three of this studies are presented here in addition to a benchmark description of the main agricultural characteristics in the concerned area. Are so reported a study on the degree of farmland fragmentation, another one on the size change dynamics of farms, and a last one dealing with farmers’ adaptation strategies in reaction to such a large project. Even though these studies have not yet all produced operational results, we hope that they will all contribute to objectivize the debate which arose when the project was launched and the observatory was set up.