Yes, you can watch planes taking off and landing from inside the terminal. The layout gives passengers in the secure area a great view of the runways.
If you are not flying and just want to watch the planes, you can see part of the secure area and have a partial view of the runways on level 2 of the terminal, near the footbridge.
There are also several outdoor areas where you can safely enjoy watching the planes. Discover the best places listed by YQB Aviation on this interactive map (available in French only).