  At present, there are discrepancies with the predictions of the standard
model in ${\bar B}^0 \to D^{*+} \ell^- {\bar\nu}_\ell$ decays, hinting at the
presence of new physics (NP) in $b \to c \tau^- {\bar\nu}$. Various NP models
have been proposed to explain the data. In this talk, I discuss how the
measurement of CP-violating observables in ${\bar B}^0 \to D^{*+} \ell^-
{\bar\nu}_\ell$ can be used to differentiate the NP scenarios.
