Civil Code, Art. 1279

In order that compensation may be proper, it is necessary: (1) That each one of the obligors be bound principally, and that he be at the same time a principal creditor of the other; (2) That both debts consist in a sum of money, or if the things due are consumable, they be of the same kind, and also of the same quality if the latter has been stated; (3) That the two debts be due; (4) That they be liquidated and demandable; (5) That over neither of them there be any retention or controversy, commenced by third persons and communicated in due time to the debtor. (1196)