I don't know exactly what you're doing, but I'll try to help.
In the restricted area, you have to active the three towers with the blue pillars and get the three platforms leading to the lower levels (if you haven't you really should activate all 6 platforms to get the Ribbon first). Follow the corridor until you reach the T-junction. Take the right path, and it should lead to the small balcony where the GG is. It's in a chest, and the chest is pretty small, so you might have troubl seeing it.