(46) the court must no lay down the guiding principles according to which the amount of compensation due may be determined.
The action of Poland which the Court has judged to be contrary to the Geneva Convention is not an expropriation – to render which lawful only the payment of fair compensation would have been wanting; it is a seizure of property, rights and interest which could not be expropriated even against compensation.
(47) It follows that the compensation due to the German government is not necessarily limited to the value of the undertaking at the moment of dispossession, plus interest to the day of payment. This limitation would only be admissible if the Polish government had had the right to expropriate, and if its wrongful act consisted merely in not having paid to the two Companies the just price of what was expropriated… such a consequence would not only be unjust, but also and above all incompatible with … the prohibition, in principle, of liquidation of the property, rights and interest of German nationals and of companies controlled by German nationals in Upper Silesia – since it would be tantamount to rendering lawful liquidation and unlawful dispossession indistinguishable in so far as their financial result are concerned.
The essential principle contained in the actual notion of an illegal act – a principle which seem to be established by international practice and in particular by the decisions of arbitral tribunals – is that reparation must, as far as possible, wipe out all the consequences of the illegal act and re-establish the situation which would, in all probability, have existed if that act had not been committed. Restitution in kind, or, if this is not possible, payment of a sum corresponding to the value which a restitution in kind would bear; the award, if need be, of damages for loss sustained which would not by covered by restitution in kind of payment in place of it – such are the principles which should serve to determine the amount of compensation due for an act contrary to international law.
(51) following question:
I. A. What was the value, on July 3rd 1922, expressed in Reichsmarks … of the undertaking …. (including the lands, buildings, equipment, stocks and processes at its disposal, supply and delivery contracts, goodwill and future prospects)?
II. What would be the value at the date of the present judgment?
I. B. What would have been the finantial results … (profits and losses) which would probably have been given by the undertaking thus constituted from july 3rd 1922 to the date of the present judgment?