Top panel: comparison between the radial velocity as calculated from the AMBRE radial velocity program and from the HARPS pipeline for the 2004 sample (~17 000 spectra). The distribution is Gaussian. Middle panel: distribution of ΔV_rad between HARPS and AMBRE radial velocities using a logarithmic scale. Bottom panel: cumulative distribution of the | ΔV_rad | in bins of 0.05 km s^-1. Almost 70% of the spectra have a | ΔV_rad | smaller than 0.6 km s^-1. Moreover, almost 90% of the spectra are found between ΔV_rad = ±1 km s^-1.