We are building a low background detector based on a gas time projection chamber surrounded by an active anti-Compton shielding. The detector will be installed near a nuclear reactor in Bugey for the experimental study of overlineνee- scattering. We give here a general description of the experiment, and an estimate of the expected counting rate and background. The construction of the time projection chamber is described in details. Results of first test measurements concerning the attenuation length and the spatial as well as energy resolution in the CF 4 fill gas are reported.