Baron Haussmann is an old demo and personal project made in Cryengine to showcase the real-time GI sytem (SVOTI) in an architecture environment.
SVOTI means Sparse Voxel Octree Total Illumination. This system can achieve high quality global illumination in real time. In this demo you can change the time of day, and look how the light reacts.
While a real time SVO is not precise enough for archviz, compared to recent Raytracing methods, it showed a decent quality and performance in a time where GI was baked.
The current version is 0.5.3, you can download it here : https://drive.google.com/open?id=0B3ZBSML7nH5ncXVUQjRVRUEyRTg