Cygnus X-3 is a high-mass X-ray binary with a Wolf-Rayet star companion and with a short orbital period. It occasionnaly becomes one of the brightest radio source among the Galactic binary systems, with major flares from its relativistic jets. In the 1970's and early 1980's, it was postulated to be a source of high and very high energy gamma rays, that generated considerable excitements in the field of gamma-ray astronomy.
With its unprecedented sensitivity, the Large Area Telescope (LAT) aboard the Fermi Gamma-Ray Space Telescope continuously scans the entire sky every ~ 3 hours and is ideally suited to probe the high energy emission of binary systems. Here, I will report the results of one year of observations with the LAT of the very crowded Cygnus region, with specific focus on the microquasar Cygnus X-3.
