Assassin's Creed III Remastered

After becoming fully Notorious (three X's to the right of your mini map), you will start to see the Jager enemies. They are actually a lot more difficult to fight than the other enemies in the game. A good place to do this is at the end of DNA Sequence 5 - Memory 2. Memories can be replayed by going to the "DNA Tracker" menu in the pause screen. You will have to climb to a rooftop and after a cutscene you will automatically get full notoriety. There will be lots of Jagers on the streets then. You must kill all 10 to get the achievement in one go.