Short answer. Generally, no. As an officious manager — someone who acts without the owner's authority — you are personally liable for contracts you signed, even in the owner's name. The owner is not bound and the supplier has no direct right of action against the owner, unless the owner later ratified your management.
What the law says
The officious manager is personally liable for contracts which he has entered into with third persons, even though he acted in the name of the owner, and there shall be no right of action between the owner and third persons.
Civil Code, Article 2152 — Gestor's Liability to Third Persons. Read the full provision →
The default rule: you are personally liable, not the owner
Article 2152 of the Civil Code states the core rule plainly: The officious manager is personally liable for contracts which he has entered into with third persons, even though he acted in the name of the owner, and there shall be no right of action between the owner and third persons. An officious manager (or gestor) is someone who steps in to manage another's business without being authorized to do so. The fact that you signed the supplier contract in the owner's name does not shift liability to the owner — the law looks at authority, not the name used in the document.
Two exceptions where the owner may be bound
The rule has two important exceptions. First, if the owner expressly or tacitly ratified the management, the contracts you made become binding on the owner. Ratification can happen through words, conduct, or by accepting the benefits of what you did. Second, if the contract involves things pertaining to the owner of the business — meaning the subject matter of the contract is something that belongs to the owner or is intrinsic to their enterprise — the owner may be bound as well. Both exceptions reflect the idea that the owner should not enjoy the fruit of your management while escaping the obligations it created.
What this means for the supplier
The supplier who dealt with you as an officious manager has no direct claim against the owner of the business — at least not under the contract itself. Their claim runs against you personally. This is a significant consequence: the supplier may have believed they were contracting with a well-established business, but legally they were contracting with you as an individual. If the owner never ratified your management and the contract does not fall within the second exception, the supplier's only remedy is to pursue you.
What you should do now
If the owner has already accepted or benefited from the contract, there is a reasonable argument that they have tacitly ratified your management and may now be bound. If no ratification has occurred, you bear the contract's obligations personally. The cleanest path forward is to seek the owner's explicit ratification — in writing — which will transfer the contractual relationship to them and release you from personal liability. If the owner refuses to ratify, you and the supplier will need to resolve matters between yourselves, and you may separately have a right to seek reimbursement from the owner for expenses you incurred on their behalf, depending on whether the management benefited them.