These are some great blueprints for Disneyland Paris Frozen Land from which we can extract a bit of information.
In comparison to the Frozen Land in Epcot, the foot print for Disneyland Paris is far more rectangular, while in Orlando it's an irregularly shaped pentagon. Both ride areas are nearly the same surface area in the range of 3200 square meters when traced (not including retail, restaurants etc...)
Orlando used an existing facility so this new purpose built facility should have fewer design limitations.
While the mountain appears to be impressive in height in the artist renders, and will no doubt be impressive in person, the height is probably in the range of 30-35 meters. This is considerably shorter than the Matterhorn or Expedition Everest. Some clever forced perspective and scaling will ensure the mountain appears much taller than it is.
The village of the Frozen Land, and castle that will be off to the right as you approach, hides the bulk of what is otherwise a rectangular box nearly 20 meters in height.
Chris