This One is in Saint Denis and can very useful for farming XP or Awards
All you need to do is go to where I am at in the video and walk up to the railing,
Now you want start the "Rest" animation by holding Down Triangle,
As the circle in the bottom right hand corner for the rest animation gets to about 75% full, You want to at the same time press and hold Square and Forward.
This will Make your character jump over the railing but still want to do the rest animation which then allows you to move into the wall.