La Crau is a flat plain of 20 kilometer diameter, cover by white pebbles, and located in the south east of France. This homogeneous bright site is used by CNES since 1987 as a test site for vicarious calibration of the SPOT-HRV cameras. The former calibration activities, up to 1997, were conducted during field campaigns devoted to the characterization of the atmosphere and of the site reflectances. Since 1987, au automatic photometric station was set up on La Crau on a 10 m height pole. This station first measures at different wavelengths, the solar extinction and the sky radiances to fully characterize the optical properties of the atmosphere. Then, on a downward looking; 862 surface radiances are collected under different view directions to characterize a 20 m* 20 m site. These radiances are converted into reflectances and a bidirectional model of the site was achieved. All these data, collected at the time of overpass of SPOT, are used to predict the incoming radiance to the sensor. Spot calibration results are compared, accounting for error bars, with other vicarious calibrations provided by CNES.