  The quasielastic charged-current (CC) tau neutrino (antineutrino)-nucleus
scattering is considered.
  The dependence of tau polarization on nuclear-structure effects is discussed
in detail.
  The description of the nucleus is based on the Mean-Field Theory (MFT).
  The ground state of nucleus is described using the Relativistic Fermi Gas
model (FG).
  The effective mass is introduced as well as the ring Random Phase
Approximation (RPA) effects are taken into account in the framework of
relativistic meson-nucleon model. The Local Density Approximation (LDA) is used
for the argon nucleus, having in mind possible application to the ICARUS
experiment. The discussion concentrates on the threshold region where the
$\tau^-$ can be unpolarized and the nuclear effects play an important role.
