Résumé
After several months of Gaia-RVS observations, many radial velocities are now available and can be compared to existing ground values. An extended catalogue of 10227 reliable ground-based RV has been compiled from different sources including our own observations of standard star candidates, and objects with good archive spectra. First conclusions are: Some 4000 comparison stars already observed several times during the 3 first months of operation show a gaussian dispersion around the ground-based value on the order of 1.1km/s; some stars show a slight evolution of their RVS measurements and are probably binaries; some RVS observations show "irregularities" now explored in details. It is particularly important to note that our 2798 primary standard star candidates (extended list), are very stable over the Gaia mission. For the others, the last ground-based campaign anticipated 10 years ago to assess their stability, should be now started.