A second miscellaneous achievement during the Venice mission (in addition to Cheers!), you'll need to head to the rat-shooting range and clear three rounds of it to receive the Teddy Bear prize. Take this to the child directly opposite from the shooting range to reunite him with his bear and receive this achievement.
Check out the video below for a full playthrough of the game showing all collectibles, miscellaneous achievements like this one, and the Moral Points I obtained (I skipped a lot of them) in order to get the Redemption achievement. The Venice mission starts at timestamp 1:05:32