  We present a method to investigate the CP quantum numbers of the Higgs boson
in the process $e^+ e^- \to Z\phi$ at a future linear collider (LC), where
$\phi$, a generic Higgs boson, is a mixture of CP-even and CP-odd states. The
procedure consist of a comparison of the data with predictions obtained from
Monte Carlo simulations corresponding to the productions of scalar and
pseudoscalar Higgs and the interference term wich constitutes a distinctive
signal of CP violation. We present estimates of the sensitivity of the method
from Monte Carlo studies using hypothetical data samples with a full LC
detector simulation taking into account the background signals.
