We used the method of Silva & Cruz (2006), which distinguishes between planetary and stellar companions by fitting transit light curves, to select the most promising CoRoT candidates to be monitored with radial-velocity measurements. Testing this method on the light curves of confirmed CoRoT exoplanetary systems shows that the estimated radius for such planets is smaller than 2 RJup, while for most of the light curves in which no planet has been detected, the secondary companion has an estimated radius larger than 2 RJup. We present preliminary results concerning other light curves for which no planet has been detected yet.