We report the optical reflectance, magnetic susceptibility, and magnetoresistance of the first stage AuCl3-GIC which has the shortest c-axis repeat distance among transition metal chloride GICs. The optical reflectance is not explained only in terms of the graphitic pi-system. The observed Pauli paramagnetic susceptibility is about three times as large as that from the graphitic pi-system. These results suggest the existence of the AuCl3-intercalate band which enhances the density of state at the Fermi although the electrons in the intercalate are more localized than those in the graphitic plane, judging from the magnetoresistance.