This paper presents a reconfigurable intelligent surface (RIS) assisted multiuser (MU) multiple-input multiple-output (MIMO) system. Instead of being applied at the remote RIS, the phase shift vector is applied at the base station (BS) by using an additional precoding stage. The overall system performance is improved by incorporating a double quadrature spatial modulation (DQSM) transmission technique. Results show that the proposed system has gains of up to 17 dB in bit error rate (BER) and a reduction in detection complexity of 51% when compared with the conventional MU-MIMO system based on spatial multiplexing (SMux). Compared with a similar system based on amplify and forward (AF) relay-assisted technique, the proposed system has up to 18 dB gain in BER performance under the same conditions and parameters. Mainly, the proposed system significantly reduces the signal processing required at the RIS.