The French permanent broadband network (RLBP) is planned to develop in Brittany, NW France, in the following year. This region mostly lies on the Armorican Massif – a peneplained remnant of the Hercynian orogen – where almost no cave exists and where human presence is widespread due to intense agriculture activities. For those two reasons, choice has be made to install the broadband sensor of the future seismological stations into 10 m deep cased boreholes. Our first realization is the BOUF station, located at Bouguenais at c.a 15 km south from Nantes, France. This site was previously instrumented for 3 years during the PyrOPE temporary deployment with a 1 m deep seismic vault. The first 6 months of measurements in the borehole shows a dramatical decrease of the seismic noise (∼10 dB) above 20 s of period compared with the previous installation. We however stress that great care should be taken during the putting in of the sensor, and in particular on the cable configuration. We propose here some indications and good practice to achieve a good quality measuring site. We also present here the results of a set of tests we performed on the structure of the borehole: diagraphy analyses, check of the welds and of the concrete, temperature profile.