Yes and No! Your own personal look on the world i 2 dimensional as you look from above and not through the eyes of your character.
Objects however are 3 dimensional. They have a height, you can climb mountains (for example climb a mountain with 3 parcels). Also if it was 2d objects you would a) be able to see whats behind a house which you cant and b) you would either not be able to see the shape and color of walls, mountains and do not recognize you have different height layers in any way.
So I rather say Tibia is a game with 3D objects but you watch everything from above which is actually a 2D view.