  In Nakamura et al.[1], the authors present evidence of shift current in the
electronic ferroelectric tetrathiafulvalene-$p$-chloranil (TTF-CA). Since the
bulk photovoltaic current in non-centrosymmetric crystals has two
contributions, namely the ballistic and shift, we explain why the experimental
data and analysis presented by the authors does not permit unambiguous
identification of shift current, and is not consistent with the mechanism of
shift.
