Yes, on the lower departure level below security of T5, in front of Prada in the gate 13 area. Traditional red box design, with a transparent back cover, you won't miss it if you are looking for it. It's emptied around 5pm 5 days a week, midday Saturday, but it has a narrow slit, it's cards and letters only. You may get something like a passport form through it, but it's well under 1 cm wide.