In the very first mission of the game, second section (after you've escaped through the Safe Room), while working your way toward the docks, you can find the newspaper offices (Dunwall Courier) on the left hand side of the street, toward the bottom of the stretch before you pass the barrier closest to the docks.
Enter and take the stairs to the top floor, disposing of guards as you wish. When you reach the top, you can find the newspaper writer hiding in one of the back rooms. Talk to him and the achievement should unlock.