  We study the density of states (DOS) and the transition temperature $T_c$ in
a dirty superconducting film with rare classical magnetic impurities of an
arbitrary strength described by the Poissonian statistics. We take into account
that the potential disorder is a source for mesoscopic fluctuations of the
local DOS, and, consequently, for the effective strength of magnetic
impurities. We find that these mesoscopic fluctuations result in a non-zero DOS
for all energies in the region of the phase diagram where without this effect
the DOS is zero within the standard mean-field theory. This mechanism can be
more efficient in filling the mean-field superconducting gap than rare
fluctuations of the potential disorder (instantons). Depending on the magnetic
impurity strength, the suppression of $T_c$ by spin-flip scattering can be
faster or slower than in the standard mean-field theory.
