Ethics and Truthfulness: The Duty Not to Lie to the Judge and the Consequences of Doing So

This page is a translation of the original Portuguese text, provided for convenience. It deals with Brazilian law. If there is any discrepancy, the Portuguese version prevails. Read the original in Portuguese

A lawsuit is not a free-for-all where any strategy goes. Anyone who litigates takes on duties of loyalty and good faith, and breaking them can be costly: bad-faith litigation exposes a party to fines, damages, and a weakened case. Understanding these limits is essential to defending your rights without crossing the line that turns a plaintiff or defendant into someone who has broken the rules of the game.

What the duty of loyalty means in a lawsuit

Article 5 of Brazil’s Code of Civil Procedure (Código de Processo Civil) states right at the outset that everyone who takes part in a lawsuit must act in good faith. This is not moral advice. It is a rule with practical consequences. Procedural good faith requires the parties, their lawyers, intervening parties, and even third parties to act with loyalty, transparency, and cooperation so that the courts can reach a fair result.

The duty rests on a simple idea: a lawsuit is a public tool for resolving disputes, not a tool for ambush. Anyone who turns to the courts asks the State to step in and, in exchange, agrees to follow rules of conduct that make a judgment reliable.

Article 77 of the Code spells out these duties. They include stating the facts truthfully, not making a claim or a defense while knowing it has no basis, and not producing evidence or taking actions that are useless or unnecessary for establishing or defending the right at issue. Violating these commands does not go unnoticed.

Bad-faith litigation: when conduct becomes a violation

Bad-faith litigation (litigância de má-fé) is the technical term for abusing the right to sue or defend. Article 80 of the Code of Civil Procedure lists the conduct that qualifies, and reading that list helps ordinary people see where legitimate defense ends and disloyalty begins.

A party acts in bad faith when it raises a claim or defense against the express text of the law or an undisputed fact, alters the truth of the facts, uses the lawsuit to achieve an illegal objective, unjustifiably resists the progress of the case, behaves recklessly, raises a manifestly unfounded procedural incident, or files an appeal with a merely delaying purpose.

For most people, the sensitive point is altering the truth of the facts. Lying about what happened, leaving out decisive information, or presenting a deliberately distorted version is not a clever strategy. It is a procedural violation that can compromise your entire case.

A distinction matters here. Arguing a bold theory, advancing a minority interpretation of the law, or telling the facts from the perspective most favorable to the client is all permitted. Disloyalty begins when there is conscious manipulation of reality or use of the lawsuit for an unlawful purpose.

Article 5 of Brazil’s Code of Civil Procedure states right at the outset that everyone who takes part in a lawsuit must act in good faith.

The practical consequences of disloyalty

The penalty for bad-faith litigation is set out in Article 81 of the Code of Civil Procedure. The judge, on his or her own initiative or at the request of a party, orders the disloyal litigant to pay a fine of one percent to ten percent of the adjusted value of the claim. When the value of the claim is negligible or cannot be estimated, the fine may be set at up to ten times the current minimum wage.

The penalty does not stop at the fine. The wrongdoer also pays damages for the losses the other party suffered, along with attorney’s fees and all the expenses that party incurred because of the abusive conduct. The financial cost therefore comes from three separate sources and can far exceed whatever benefit the maneuver was supposed to bring.

There is also a less visible effect, which is often more serious. When the judge sees that a party has lied or acted disloyally, the credibility of that party’s entire body of evidence is shaken. True arguments start to be read with suspicion, and the main theory of the case loses strength at the decisive moment of the judgment.

Damage to trust is usually irreversible within that case. Rebuilding credibility after a glaring contradiction is nearly impossible, and the practical result is a weakened defense at exactly the moment it most needed to be solid.

How to cooperate with the court without hurting your defense

There is a common misconception: that telling the truth means handing over the case. It does not. The duty of truthfulness does not force anyone to produce evidence against themselves indiscriminately, but it does forbid lying and distortion. A legitimate defense works with the real facts, chooses the most favorable legal grounds, and presents the client’s version skillfully, without inventing realities.

The safe path involves a few concrete precautions. The first is to gather documents and organize the timeline of events before making any statement, so that the account presented in court matches a reality you can prove.

The second is to separate what you doubt from what you know. When there is no proof of a particular point, the right approach is to support your position through the legal framing, not to manufacture a fact to fill the gap. Strategically leaving out an argument is different from falsely asserting that something happened.

The third is to entrust the technical handling to a lawyer. It is the professional’s job to translate the client’s story into appropriate procedural language, separating what helps from what hurts and preventing an impulsive remark from becoming an improper admission or a contradiction the opposing party can exploit.

In this sense, cooperating with the court is an act of defensive intelligence. A party that is consistent, transparent, and respectful of the rules earns the trust of the judge, and that trust tends to carry weight on points where the law leaves room for interpretation.

The role of cooperation between the parties

The Code of Civil Procedure embraced the principle of cooperation. The rule starts from the recognition that, although the parties have opposing interests, they all share the goal of obtaining a fair and effective decision on the merits within a reasonable time.

Cooperating does not mean giving up your defense. It means avoiding acts that only get in the way of the case’s progress. Delaying requests, unfounded appeals, and procedural incidents created only to buy time violate this principle and expose the party to the penalties described above.

A cooperative approach pays off in two ways. On one hand, the case moves faster, which benefits whoever is actually in the right. On the other, the loyal party protects its standing before the court and reduces the risk of penalties that could eat up a significant part of any eventual recovery.

Procedural loyalty, then, is not merely an ethical requirement imposed from above. It is also a strategic choice that protects your assets, strengthens your case, and improves your chances of a favorable outcome.

Frequently Asked Questions

Can telling the whole truth in a lawsuit hurt me?

The duty of truthfulness forbids lying and distorting the facts, but it does not require a party to lay out, in a disorganized way, everything that could be used against them. A legitimate defense works with the real facts and chooses the most favorable legal grounds. The risk arises when a person, without professional guidance, makes impulsive statements that turn into contradictions. That is why having a lawyer handle the case is decisive: the lawyer presents the client’s true version with the right technique, without inventing realities and without conceding points that could be argued on purely legal grounds.

How much is the fine for bad-faith litigation?

The fine ranges from one percent to ten percent of the adjusted value of the claim, under Article 81 of the Code of Civil Procedure. When the value of the claim is negligible or cannot be estimated, the penalty can reach ten times the current minimum wage. In addition to the fine, the disloyal litigant must pay damages for the other party’s losses, attorney’s fees, and the expenses that party incurred because of the abusive conduct. Together, these amounts usually far exceed any supposed advantage gained from the maneuver.

Is arguing a bold theory the same as litigating in bad faith?

No. Advancing a minority interpretation of the law, presenting an innovative theory, or telling the facts from the perspective most favorable to the client falls within the normal exercise of the right of defense. Bad-faith litigation requires abuse, such as altering the truth of the facts, raising a claim against the express text of the law, using the lawsuit for an illegal purpose, or appealing only to delay. The difference lies in good faith: arguing with a solid basis is legitimate, even if the theory is risky, while manipulating reality or using the lawsuit as an improper weapon is what makes the conduct punishable.

As informações deste artigo são de caráter informativo e não substituem consulta jurídica individualizada. Cada caso possui particularidades que exigem análise específica.