  Hybrid reflective intelligent surfaces (HRISs) can support localization in
sixth-generation (6G) networks thanks to their ability to generate narrow beams
and at the same time receive and process locally the impinging signals. In this
paper, we propose a novel protocol for user localization in a network with an
HRIS. The protocol includes two steps. In the first step, the HRIS operates in
full absorption mode and the user equipment (UE) transmits a signal that is
locally processed at the HRIS to estimate the angle of arrival (AoA). In the
second step, the base station transmits a downlink reference signal to the UE,
and the HRIS superimposes a message by a backscatter modulation. The message
contains information on the previously estimated AoA. Lastly, the UE, knowing
the position of the HRIS, estimates the time of flight (ToF) from the signal of
the second step and demodulates the information on the AoA to obtain an
estimate of its location. Numerical results confirm the effectiveness of the
proposed solution, also in comparison with the Cram\'er Rao lower bound on the
estimated quantities.nd on the estimated quantities.
