Import From blender : Model's mesh are totally flattened

I created a Model on blender . But when i want to import it on Unity all the mesh are first not in the good rotation but this not the biggest problem , all of my mesh are totally flattened.

On blender i export it as a FBX , And on Unity i Import the double model ( the blender one and the FBX ) to try if it was maybe a problem of type , But it’s the same problem.

Like you can see on the picture I have my hotel in grey , and I import a simple version of my hotel to use it for the Mesh Collider but this one is not at all like my Original Hotel.

Picture : or

Edit1 : the scale on blender :

Are you using the last version of Blender? And please, to we can help reupload you image file, it’s missing

Ps: Sorry For English