This pass is basically using most of the GI settings and environment to light up the place. No lights were place just yet. The supposedly light fixtures were simply made with self-illuminating materials.
My post-processed image. I simply adjusted the curves, and enhanced the colours by a number of Layers in Photoshop...either by adding photo filters and mixing up with soft light effects and blurring. Other details were also added, such as the wine bottles by the bar and painting some of the specular reflections.