Renault (not the car manufacturer, duh) is some thug who's found in the hostel on the Paris streets level. He tells you that the baker at #15 keeps zyme and asks for 6 vials. If you find him and talk to him, you can tell him that you don't get paid in zyme, in which case he'll increase the price per vial. Do not reply negatively for a second time, because that turns both him and his bodyguard hostile.
Go to #15, that's the bakery. In Revision stealing the vials is harder since there is a camera at one of the corners. Going in either through the front or the back door (both can be broken with a powerful enough melee weapon), go behind the counter and while looking at the cash register machine, turn 90 degrees to your left. There is a shelf on the counter. Open it, pick up all the vials and return to Renault. The achievement pops as soon as the transaction is complete.