What you see here happens to be real world people, filmed in the real world, where all of it has been shot in Madrid. Not only that, just to make sure that you have an idea on just how close it gets to the real deal, there is an insert located at the lower left hand corner of the video which will show just how closely this particular fan-made trailer will follow in the footsteps of the original GTA 5 trailer.
In fact, many things do fall into place with one another, although there are some instances where the shot itself moves away from what the original offers, with the oil wells being the most noticeable one. Perhaps the day will arrive when graphics on the computer or console arrive at a photo-realistic level in real time rendering, and the trailer above could be that of the actual game then.