Article 1054 of Civil Code

1 - A pledge of a debt shall not be effective against the debtor unless he is notified of the pledge or accepts it in accordance with the rules governing assignment. 2 - This pledge shall not be effective against third parties until the pledgee creditor or the agreed custodian takes possession of the instrument evidencing the pledged debt and the debtor is notified of the pledge, or from the established date of his acceptance.