Clean Sweep is a secret achievement/trophy in the System Rift expansion for Deus Ex: Mankind Divided. To obtain it, you must complete the entire Jensen Story without killing anyone.
The only areas where you will find enemies that are by default hostile to you are around the Zatopek bar, and the initial section of the Palisade Blade, where Tarvos Security Services guards are patrolling. Once you reach the server area in the Blade, there will be no more human security, so you cannot miss the achievement if you have killed no one by this point and decide to use the hatch to exit the Blade instead of the main elevator.