Lighting: The foreground space is lit with an Omni and instance and the background space has an exterior Infinite and Area light sources aimed at the window. The wall objects do have spots (6) lighting them. The walls and ceiling materials use the Luminance (20%) channel. Illumination Gen. GI (45%) used on the front walls and Receive GI (50%) on the rear wall.
Render Settings GI: S 100%, Acc 40%, Prepass 1/1, DD 1, Stoch 600, Min 100, Max 500. Options: Ray D 3, Shadow D 3.