Constitutional appeal; justiciability of completed private-law transactions. A state-law complaint cannot be used to challenge and annul a bilateral private-law sale that has already been executed and in which third parties participate. If a federal judgment would have no practical effect, the appeal is moot and the Federal Court will not enter into it (consid. 1). The legality and validity of the transaction must be determined in ordinary civil proceedings; the constitutional judgment has no binding prejudicial effect for later civil claims or liability actions, where the ordinary judge freely reviews the transaction and the conduct of the authorities.