Importing FBX files in Unity with the correct scale, rotation, and axis is fraught.

FBX files seem to be in cm by default, but can support other units. Other unit scales are achieved in FBX by by setting GlobalSettings→Properties70→UnitScaleFactor property in the file. For example, when a 1 meter cube in 'meters' should be stored in an fbx file like:

 - GlobalSettings->Properties70->UnitScaleFactor = (100.0)   # The 'unit' is 100 * 1cm 
 - CubeObject
    - Lcl Scaling = (1,1,1)