  We investigate the magnetic response of thin NiI$_2$ flakes for temperatures
above 80~K. Since no magnetic ordering is expected for bulk NiI$_2$, we observe
clear paramagnetic response for massive NiI$_2$ single crystals. In contrast,
thin NiI$_2$ flakes show well-defined ferromagnetic hysteresis loop within
$\pm2$~kOe field range. The value of the response does not scale with the
sample mass, ferromagnetic hysteresis can be seen for any flake orientation in
the external field, so it originates from the sample surface, possibly, due to
the anisotropic exchange (Kitaev interaction). The observed ferromagnetism is
weakly sensitive to temperature up to 300~K. If a flake is multiply exposed to
air, ferromagnetic hysteresis is accompanied by the periodic modulation of the
magnetization curves, which is usually a fingerprint of the multiferroic state.
While NiI$_2$ flakes can not be considered as multiferroics above 80~K, surface
degradation due to the crystallohydrate formation decreases the symmetry of
NiI$_2$ surface, which produces the surface ferroelectric polarization in
addition to the described above ferromagnetic one.
