  The X and gamma-ray observations of the source GRB 031203 by INTEGRAL are
interpreted within our theoretical model. In addition to a complete space-time
parametrization of the GRB, we specifically assume that the afterglow emission
originates from a thermal spectrum in the co-moving frame of the expanding
baryonic matter shell. By determining the two free parameters of the model and
estimating the density and filamentary structure of the ISM, we reproduce the
observed luminosity in the 20-200 keV energy band. As in previous sources, the
prompt radiation is shown to coincide with the peak of the afterglow and the
luminosity substructure are shown to originate in the filamentary structure of
the ISM. We predict a clear hard-to-soft behavior in the instantaneous spectra.
The time-integrated spectrum over 20 seconds observed by INTEGRAL is well
fitted. Despite this source has been considered "unusual", it appears to us a
normal low energetic GRB.
