I build this realtime project in about 2 month. Its a commercial center located in tehran. Including 16bit float lightmap.
The result is correct tonemapping.
Tip about gamma correction:
1. In a software render (for bake) use gamma corrected texture or SRGB. Then use a output gamma correction of 2.2 in render settings and bake your lightmap.
2. use SRGB in your HLSL shader. Finally use HDR to output gamma 2.2.
The same method should apply also for dynamic lighting.
That was what i learn during this project.