A garage in a residential building is included in the unusable area of the building, which is taxed at 0.15% for a residential unit.  A detached garage (function is the same) located one metre from the dwelling house and belonging (ownership, functional) to the house is of course taxed at 0.5% !
Where is the reason, the logical explanation? It comes to a tax as high as for the whole apartment house.
A correction is absolutely necessary here.