The KM3NeT team of the Neutrino group of Subatech, Nantes in France, participates to the instrument construction by taking in charge a part of the integration of the optical sensor modules. These modules are instrumented glass spheres with a diameter of 50 diameter, equipped with 31 photo-multipliers and the control and acquisition systems. They are themselves integrated in groups of 18 to form detection units. Ultimately, with many KM3NeT institutes working together on producing the units, a total of 115 and 330 detection units will make respectively the ORCA and ARCA detectors accounting for more than 6000 optical modules. The picture shows the team of Subatech with the first optical sensor module of a long series.