  In a recent letter [D. Poletti et al., EPL 93, 37008 (2011)] a model of
attractive spinless fermions on the honeycomb lattice at half filling has been
studied by mean-field theory, where distinct homogenous phases at rather large
attraction strength $V>3.36$, separated by (topological) phase transitions,
have been predicted. In this comment we argue that without additional
interactions the ground states in these phases are not stable against phase
separation. We determine the onset of phase separation at half filling
$V_{ps}\approx 1.7$ by means of infinite projected entangled-pair states
(iPEPS) and exact diagonalization.
