  We analysed the chromatic data of the planetary transits observed with CoRoT
to supply homogeneous time series in each of the CoRoT colours. In a first
step, we cleaned the chromatic light curves from the contamination of nearby
stars and removed outliers and trends caused by anything different from the
planetary transits. Then, we simultaneously fitted the chromatic transits of
each planet, obtaining a common solution for the orbital parameters i, t0 and
a/Rs, with a particular care in the fitting for different limb-darkening
parameters. The planet-to-star radius ratios in the CoRoT colours are
compatible when considering one planet at a time, but the ensemble of low-mass
planets seems to show a peculiar behaviour of the radius ratios.
