Short answer. Yes. Article 1546 of the Civil Code draws a clear exception: a seller's statement of opinion is normally not a warranty, but it becomes one if the seller made it as an expert and the buyer relied on it. The expert's word carries legal weight that an ordinary seller's opinion does not.
What the law says
No affirmation of the value of the thing, nor any statement purporting to be a statement of the seller's opinion only, shall be construed as a warranty, unless the seller made such affirmation or statement as an expert and it was relied upon by the buyer.
Civil Code, Article 1546 — Express Warranty Versus Dealer's Talk. Read the full provision →
The general rule: opinions are not warranties
Article 1546 of the Civil Code sets out two categories of seller statements and treats them very differently. A statement of fact — an affirmation about what a thing actually is or does — can become an express warranty if it naturally tends to induce purchase and the buyer acts on it. A statement of opinion, by contrast, is not a warranty as a general rule. Value statements and pure opinions are excluded from warranty protection because buyers are expected to form their own judgments on such matters.
The expert exception
The exception in Article 1546 is precise: "unless the seller made such affirmation or statement as an expert and it was relied upon by the buyer." Both elements must be present. The seller must have presented the opinion in the capacity of an expert — someone with professional knowledge, training, or recognized authority on the matter. And the buyer must have relied on that opinion in deciding to purchase. When both conditions are met, what would otherwise be mere opinion becomes a binding warranty, enforceable against the seller if it proves false.
Why expert opinions carry more weight
The distinction makes practical sense. When a non-specialist says "I think this is a good machine," the buyer knows they are hearing a lay opinion and should verify it independently. When the seller is a licensed engineer opining on structural integrity, or an accredited gemologist attesting to a stone's quality, the buyer reasonably treats that opinion as reliable information, not mere conversation. The law recognizes this asymmetry: the buyer's reliance on an expert opinion is objectively more reasonable, and holding the expert-seller to it reflects that heightened trust.
What this means if the expert opinion was wrong
If a seller gave an expert opinion that turned out to be false, and the buyer purchased the thing relying on that opinion, the buyer has a warranty claim. The remedy may include rescission of the sale or damages, depending on the circumstances. The buyer must be able to show two things: that the seller held himself out as an expert, and that the buyer actually relied on the opinion rather than making an independent assessment. If the buyer independently verified the claim or did not consider the seller's statement in making the decision, the reliance element may not be established.