  We investigate the possible effects of short-baseline antinu_e disappearance
implied by the reactor antineutrino anomaly on the Double-Chooz determination
of theta_{13} through the normalization of the initial antineutrino flux with
the Bugey-4 measurement. We show that the effects are negligible and the value
of theta_{13} obtained by the Double-Chooz collaboration is accurate only if
Delta m^2_{41} is larger than about 3 eV^2. For smaller values of Delta
m^2_{41} the short-baseline oscillations are not fully averaged at Bugey-4 and
the uncertainties due to the reactor antineutrino anomaly can be of the same
order of magnitude of the intrinsic Double-Chooz uncertainties.
