As you can see, the actor walks while the camera follows him. What I should do is to fill the bottom of the floor with smoke or "mist" that is filling the room. This also seems to mean that, of course, the smoke would go towards the camera.
So.. Ok, I'll track the shot and rotoscope the actor but what about the smoke itself? This magic "mist"? Should I search or use some kind of artebat? It seems quite the problem here.
I did a test and there should be no issue in tracking the camera. You can then create the smoke several different ways - Particle Illusion, Stock footage, or Trapcode Form. You ca even use a 3d displacement plugin like FreeForm Pro. However the biggest issue will be the interaction of the actor with the smoke. As he walks through it, there should be swirls and the smoke should move.
The easiest way would be to use a 3d particle system in C4d and create turbulence by matching the position of the actor. This tutorial may be a starting point: