Direct imaging of Ceres has been performed using an adaptive optics system, developed by Laserdot (France), Paris Observatory (Meudon, France), ONERA (France), and ESO. The diffraction limit of the 3.6-m ESO telescope (La Silla, Chile) was obtained at near infrared wavelengths in the K, L ′, and M bands (0.13, 0.25, and 0.30 arcsec, respectively).Several physical parameters for Ceres are deduced from these observations. The rotation is prograde (consistent with previous observations). The pole orientation is λ = 332 ± 5° and β = 70 ± 15°, implying a low obliquity with respect to Ceres orbital plane. The estimated thermal inertia of the regolith is 3.8 ± 1.4 × 104 erg cm-2 sec-1/2K-1. The measured temperature of the warmest area is 235 ± 4 K. The value of the mean radius, 484 ± 20 km, is consistent with earlier values obtained by stellar occultation and thermal infrared photometry. No albedo variations can be detected in reflected light and the center-to-limb distribution clearly departs from a Lambertian distribution.