The sanction of the GAAR lies in denying of a tax advantage because it would go against the object or purpose of the applicable tax law.
There is very little court practice on that matter, but I imagine it will be less applicable cross-border. No jurisdiction would be interested in reducing its tax base or the amount of taxes it gets, so there is an ingrained conflict. Moreover, no jurisdiction is interested in contributing resources to reduce its tax base so one party never benefits from the co-operation.
ATAD makes it clear, however, that taxpayers should have the “right to choose the most tax-efficient structure”︀ for their commercial affairs, limited only by the requirement that they not be “non-genuine”.