Short answer. Yes, to a degree. Article 2068 provides that if you paid the debt as guarantor without notifying the debtor, he may raise against your reimbursement claim all the defenses he could have set up against the creditor when payment was made. Notifying him first is what avoids this.
What the law says
If the guarantor should pay without notifying the debtor, the latter may enforce against him all the defenses which he could have set up against the creditor at the time the payment was made.
Civil Code, Article 2068 — Payment Without Notice. Read the full provision →
Reimbursement comes with a condition
A guarantor who pays the creditor is generally entitled to recover from the debtor what he laid out. But the law expects the guarantor to keep the debtor in the loop, and it penalises a payment made behind his back. Article 2068 states the consequence squarely: If the guarantor should pay without notifying the debtor, the latter may enforce against him all the defenses which he could have set up against the creditor at the time the payment was made. Your reimbursement claim is not lost, but it is exposed to every objection the debtor himself could have used to resist the creditor.
What those defenses can be
The defenses transferred to the debtor are whatever he could have thrown at the creditor when you paid. That might be that the debt had already been paid or partly extinguished, that it was subject to a set-off against something the creditor owed the debtor, that the claim had prescribed, or that the obligation was unenforceable or void for some reason. If any of these was available at that moment, you effectively paid something the debtor did not fully or validly owe, and he may now hold that against you instead of reimbursing in full.
Why notice matters so much
The requirement of notice is not a formality. Warning the debtor before you pay gives him the chance to say "do not pay — it is already settled," or "there is a defense here." By paying silently you deprive him of that chance and take on the risk yourself; the law will not let your haste enlarge his liability. Notice protects the debtor from being made to reimburse a payment he could have prevented or reduced, and it protects you by flushing out any problem with the debt before your money leaves your hands.
What to do
Before paying as a guarantor, tell the debtor and ask whether there is any reason not to pay or any defense to the creditor's demand, and keep proof that you gave that notice. If you have already paid without notifying him, be prepared for him to test whether the underlying debt was genuinely and fully owed at the time — because that is precisely what Article 2068 now lets him do. Your remedy for the balance he truly owed remains, but you may have to establish that the debt stood, defenses and all, when you settled it.