In the final mission of 'The Knife of Dunwall', make your way to the top of the empress statue (on the outside of the building).
The easiest way up is to climb the chain from when you first get in, and then head out the first window on the left after you have dealt with the three guards in that hallway. From inside the hall blink to the top of the stone wall support/pillar you can see from just inside the window. From there you should be able to reach the statue, especially if you have upgraded to level two. There is a guard patrolling the ground below, so just wait for him to come by, and then jump off and get him. A save from the crown is nice, as if you have played Dishonored 2, I found this jump to be slightly harder than the one from Addamire.
Once you kill him, it should record a video, then a few to many seconds longer than I would have liked, it popped.