Just buy 3 drinks from the bartender during the Venice mission. Unfortunately doing so also gives you a negative Moral Point (negatively impacts Redemption achievement). You can counteract it by paying him for the damages when you wake up. However, I didn't bother doing so and still got Redemption at the end of the game.
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