The agent may… acquire rights and contract obligations for the principal without the need to act in his name, when the third party is indifferent to know with whom he is contracting. This, in the case of contracts that generate obligations, is not frequent, since the third party will be interested, as a general rule, in knowing whom he will have as creditor and above all as debtor, even in those cases in which the contract is executed in the present, since litigation may always arise later for partial non-performance or for defects or hidden defects in the delivered objects. We understand, therefore, that if the agent buys or sells a thing on behalf of another person, but in his own name, the third party with whom he contracts only binds himself and acquires rights towards him.
In acts of acquisition of movable property or assignment of receivables, the transferor does not, as a general rule, care whether the transferee acquires the thing or the receivable for himself or on behalf of another. In the case of alienations solvendi causa, the debt is discharged even if the creditor, without the debtor’s knowledge, acquires for another the thing or the claim that he gives in payment. Likewise the donation remains perfect, even if the donee makes a third party the owner of the object donated, on whose behalf he works. The possibility of making another the owner without carrying out the act of acquisition in his name has importance in relation to the much discussed problem of the acquisition of property by the agent and especially with regard to purchase commissions. Since the commission agent buys in his own name, it seems that the ownership of the things purchased should be assigned to him, and this was, in fact, the point of view of the old Code of Obligations, in which the principal was recognized a privilege of separation in case of bankruptcy of the agent: this privilege would have been useless and impossible if the things acquired for the principal were already his property. In the current Code of Obligations the situation has changed. Now, in general, the seller is indifferent as to who owns the thing sold, so that the agent can perfectly well, even contracting in his own name, acquire the thing for the principal. The enforceable intention on the part of the agent must be taken for granted, since in doing so he is merely fulfilling the duty imposed on him by the mandate. However, for the principal to become immediately the owner, it is necessary that the identity of the thing acquired on his behalf be evidenced. If the agent buys it as a part of a quantity of things of the same kind, the property does not pass to the principal until the separation of the things destined to him takes place.
If the agent enters into a contract in his own name in which it is important for the third party to know who the other contracting party is, there will be a case of indirect representation; that is to say, the receivables and obligations arising from this contract will be subject to the agent, as long as the latter does not assign or transfer them to the principal….
… When the plaintiff affirms that the defendant contracted with him in his own name and the latter affirms that he contracted in the name of another person… we understand that this attitude of the defendant must be interpreted as a denial of the facts affirmed by the plaintiff and that, therefore, the burden of proof must be imposed on the latter…
… Since it is the agent himself who contracts… for all matters relating to the elements and requirements of contracting, the person of the agent… capacity to act… contract… between absent persons… consensus or agreement of wills… interpretation of the legal transaction… vices of consent… good faith necessary for acquisition a non domino… The person of the principal is not usually taken into account… when the agent is responsible for the choice of the contract to be concluded. But if the principal is indirectly involved in the conclusion of the contract by giving the agent specific instructions, ordering him, for example, to buy a certain thing, his will and his knowledge or ignorance of the facts cannot be disregarded. In such cases, the agent’s ignorance does not excuse the principal if he knew or should have known the circumstance in question. Thus, for example, if the agent acts in good faith, but following specific instructions of the principal, and the principal proceeds with malice, the ownership of movables cannot be recognized under the rule of bona fide possession; otherwise it would be easy to circumvent the requirement of good faith by commissioning another to buy the object instead of doing it oneself. The agent’s mistake does not invalidate the contract either if the principal, when giving instructions, knew the facts about which his mistake is made….. The agent… is not a third party… for the purpose of fraud.