(1) If two persons are bound to each other by obligations whose subject is of the same kind and both of which have become due, each obligor may make a set-off to the extent of the amount corresponding to that of his or her obligation; provided, this shall not apply where the nature of the obligations does not so permit.
(2) The preceding paragraph shall not apply to where the parties have declared an intention to the contrary; provided, such declaration of intention cannot be so set up against a third person acting in good faith.