Short answer. A common carrier can validly agree, in advance, to limit its liability for ordinary negligence toward a gratuitous passenger — but never for wilful acts or gross negligence. And a mere reduced fare, as opposed to a truly free ride, does not by itself justify limiting liability at all.
What the law says
When a passenger is carried gratuitously, a stipulation limiting the common carrier's liability for negligence is valid, but not for wilful acts or gross negligence.
Civil Code, Article 1758 — Gratuitous Passengers. Read the full provision →
A gratuitous ride does allow some limitation
Article 1758 addresses passengers carried gratuitously — genuinely free of charge, not merely at a discount. In that situation, the article says "a stipulation limiting the common carrier's liability for negligence is valid." So a carrier and a free passenger can validly agree in advance to cap or limit the carrier's responsibility for ordinary negligence. This is a real exception to how strictly common carriers are normally held liable to paying passengers, and it exists specifically because no fare was charged for the ride.
But the limitation has a hard boundary
The same sentence draws the line immediately: the valid limitation is "not for wilful acts or gross negligence." No matter what the carrier and the gratuitous passenger agreed to beforehand, that agreement cannot excuse or cap liability for conduct that is deliberate or grossly negligent. A driver's intentional misconduct, or carelessness so extreme it amounts to gross negligence, remains fully actionable regardless of any stipulation limiting liability for a free ride.
A cheaper fare is not the same as a free ride
The article closes with a rule that matters for anyone who paid something, even a token amount: "the reduction of fare does not justify any limitation of the common carrier's liability." Only a genuinely gratuitous passenger — someone who paid nothing at all — falls within the exception the article creates. A passenger who paid a discounted fare is still owed the carrier's ordinary standard of liability, with no room for a limiting stipulation on the strength of the discount alone.
What this means for someone hurt on a free ride
If you were hurt while riding entirely free of charge, the first question is what the stipulation limiting liability actually covered, and the second is what caused the injury. A limitation that was validly agreed to may cut down the carrier's liability for ordinary carelessness. But if what happened amounts to gross negligence or a deliberate act, the article does not let any stipulation reach that far — the carrier remains fully liable regardless of the free ride and regardless of what was agreed beforehand.