  The Hall resistance of a homogeneous electron system is well known to be
anti-symmetric with respect to the magnetic field and the sign of charge
carriers. We have observed that such symmetries no longer hold in planar hybrid
structures consisting of partly single layer graphene (SLG) and partly bilayer
graphene (BLG) in the quantum Hall (QH) regime. In particular, the Hall
resistance (R12xy) across the SLG and BLG interface is observed to exhibit
quantized plateaus that switch between those characteristic of SLG QH states
and BLG QH states when either the sign of the charge carriers (controlled by a
back gate) or the direction of the magnetic field is reversed. Simultaneously
reversing both the carrier type and the magnetic field gives rise to the same
quantized Hall resistances. The observed SLG-BLG interface QH states, with
characteristic asymmetries with respect to the signs of carriers and magnetic
field, are determined only by the chirality of the QH edge states and can be
explained by a Landauer-B\"uttiker analysis applied to such graphene hybrid
structures involving two regions of different Landau level (LL) structures.
