This one is making sure that no one of the guards makes it to an alarm bell and starts ringing it. Using the secret entrance into Notre-Dame from the tunnels is a great step in that direction. After that take a little time to enter stealth mode. A lot of sneaking is still needed. The good news is the nearest bell is on the far side of the wall, toward the front of the church. Still, do not let any of the Extremists or break away from any encounters. If you can avoid them all together, the better. Make your way through either carefully avoiding the guards or just killing them if they notice you.
- Kills from hiding spots 0/2
- Don't trigger any alarms