"Kills from hiding spots" is a mission objective in Sequence 3 / Memory 02: Confessions
Walkthrough
Both kills take a little time. You need to head to the Northern interior of Notre-Dame. Slip past or assassinate the guards as you go through the church.
On the Northern side, you will see Sivert enter the Confessional. He has 2 nearby guards for you to deal with. There is also a hay stack that you can use as a hiding place. Utilize the Last Known Position to lure both of them over, one at a time. When they are in range, kill them from the Hay.
Optional Objectives
- Kills from hiding spots 0/2
- Don't trigger any alarms