The name given to an agreement announcing four important rules of international law effected between the principal European powers at the Congress of Paris in 1856. These rules are: (1) Privateering is and remains abolished; (2) the neutral flag covers enemy’s goods, except contraband of war; (3) neutral goods, except contraband of war , are not liable to confiscation under a hostile flag ; (4) blockades, to be binding, must be effective