ANTARES (Astronomy with a Neutrino Telescope and Abyss environmental RESearch) is the largest neutrino detector currently operating in the Northern hemisphere. The telescope is designed to search for high-energy neutrinos originating from galactic and extra-galactic sources. The detection principle relies on the observation of Cerenkov light emitted by charged leptons resulting from charged current neutrino interactions in the medium surrounding the detector. The detector is now complete and is composed of twelve lines (a total of 900 photomultipliers), placed at a depth of about 2500 meters 40 km off the coast of Toulon, France. The first five lines of the detector have been working continuously for almost one year. The performance and lon...