After breaking into Taine's apartment Nicole and the detective are sure that they entered the murderer's nest. They do need a proof however in order to call the police. Bonnet takes photos (at a close up) of the boards on the right, where you can read pretty much everything about the psycho. One can assume that past victims are on the board on the left and the upcoming ones are on the right.
Then Nicole approaches the table in the lower left corner and browses through the stuff laying on it (close up) and takes a photo of all those things. She notices some pictures from her stay in France and an unfinished puppet. She takes a finger print from the cup on the right using the foil. She then heads to the kitchen (on the right) where she finds a disassembled monkey wrench..
She takes it back to the board and to the chest of drawers standing nearby. She opens the top drawer (zoom in) and takes out Marc Taine's driving license (which can be looked at closeup). After closing the drawer she moves the chest of drawers to the left and examines the wall behind it, as plaster is a bit different from that in the rest of the room.
She tries to smash it with the monkey wrench, but it needs to be reassembled first (left click on it in the inventory) After four hits the wall will crumble. Now Nicole needs to do is open the lock using the driving license.
In the new room Nicole finds a freezer and within it a body of the person form the driving license. Nicole decides to leave, but when she gets to the door she finds out that the other room is in flames.
Not hesitating Nicole grabs a blanket from the right and throws it into the bucket of water near the freezer. Hiding behind this wet cover she goes through the door (use the blanket on the door) and runs away from the apartment. Back in the street she gets into her car and decides to go to Spain (green flag on the GPS).