To scan this QR code located near your northwest hideout in the district, head to the southwest and you should find a winding walkway there. There's a corner camera that you can hack. Use this camera to find another camera installed in the middle of the building ahead (it's out of range on foot). From there, you can scan the code to the east.
Go to the location of the QR Code in the map then cross the street to the west. Find the high-rise camera in the corner of the building beside the archway. Use that camera to scan the code across the street.
The camera you need to hack is located to the northeast. This is the small building right in front of the water tower structure.