  The analysis of the CoRoT space mission data was performed aiming to test a
method that selects, among the several light curves observed, the transiting
systems that likely host a low-mass star orbiting the main target. The method
identifies stellar companions by fitting a model to the observed transits.
Applying this model, that uses equations like Kepler's third law and an
empirical mass-radius relation, it is possible to estimate the mass and radius
of the primary and secondary objects as well as the semimajor axis and
inclination angle of the orbit. We focus on how the method can be used in the
characterisation of transiting systems having a low-mass stellar companion with
no need to be monitored with radial-velocity measurements or ground-based
photometric observations. The model, which provides a good estimate of the
system parameters, is also useful as a complementary approach to select
possible planetary candidates. A list of confirmed binaries together with our
estimate of their parameters are presented. The characterisation of the first
twelve detected CoRoT exoplanetary systems was also performed and agrees very
well with the results of their respective announcement papers. The comparison
with confirmed systems validates our method, specially when the radius of the
secondary companion is smaller than 1.5 Rjup, in the case of planets, or larger
than 2 Rjup, in the case of low-mass stars. Intermediate situations are not
conclusive.
