Goal: Print the normal of a given face at a given location in space.

Code:

face_id = 20 #Current selection in ExtAPI.SelectionManager.CurrentSelection
point = (.01,.015,0.) #point in xyz space in the CAD unit system

#get the face object
face = DataModel.GeoData.GeoEntityById(face_id)

#get the projected point on the geometry (a curvilinar abscissa for an edge, (u,v) for a face)
u,v = face.ParamAtPoint(point)

#print the normal at the point
print(face.NormalAtParam(param))