This achievement is earned at the junction at the end of the second act where you play Paul again. During this junction you need to decide whether you want to deal with Paul personally or let Hatch deal with him. This achievement is earned for choosing the Personal path where you do it yourself.
Note that you can make this choice, then immediately replay this section and make the other to unlock both achievements if you don't want to worry about replaying it toward the end of the game. Make sure you do not replay a junction choice until you have completed all of the collectible achievements since doing so will change/move many of the collectibles, essentially requiring you to refind them.