Introduction

On August 11, 2026, the Court of Appeal ruled for the first time on the sanction applicable to the deliberate use of non-existent decisions generated by artificial intelligence by an unrepresented litigant[1] . Finding this to be a substantial breach in the conduct of the proceeding within the meaning of art. 342 C.C.P., the Court ordered the appellant to pay the respondent $1,000 in legal costs, in addition to bearing the costs of the appeal.

Background

The dispute involved two former spouses, neither of whom was represented by counsel at first instance or on appeal, regarding the corollary relief arising from their divorce. The principal appeal, which centred primarily on the assessment of the partitionable value of the respondent’s pension funds, was dismissed. The incidental appeal sought compensation for the time lost and the travel expenses incurred as a result of the appellant’s unfounded opposition to the respondent’s application for an extension of time to file her memorandum, his unnecessary applications before the Court, and his references to non-existent case law generated using artificial intelligence. It is allowed in part, with respect to the last issue. This is the one that merits attention.

The Breach

In support of several of his grounds of appeal, the appellant relied on two Supreme Court judgments and two Court of Appeal judgments that do not exist. He ascribed to those decisions legal principles, no more real than the judgments themselves, which he reproduced as quotations. It was not until reply, and only when questioned by members of the Court, that he conceded that these authorities were the product of the artificial intelligence ChatGPT. He then acknowledged that he had discovered they did not exist during a consultation with counsel before filing his memorandum, but had not considered it necessary to remove them.

The Court cites the Opinion on the Use of Artificial Intelligence before the Court of Appeal, which requires litigants to exercise caution when using these tools, to ensure the reliability of the sources cited, and to involve human oversight in verifying the final output. No one can presume that the result obtained is not the product of a hallucination, the Court notes, which is why parties must support their submissions with legislation and regulations, case law and academic commentaries drawn from reliable sources such as court websites and recognized publishers or databases.

After reviewing its recent rulings on the scope of article 342 C.C.P.[2], the Court concludes that misleading the court by deliberately supporting one’s arguments with non-existent decisions constitutes a serious breach. It emphasizes that this phenomenon is not limited to the Court of Appeal, as the Court of Québec[3] and the Superior Court[4] have recently faced similar issues.

The Sanction

In this case, the Court found that the unnecessary and costly waste of time occasioned by the opposing party’s use of unreliable sources warranted compensation.

The respondent sought $5,000. Having regard to the appellant’s financial circumstances, the Court exercised its discretion to reduce that amount to $1,000, and further ordered the appellant to bear the costs of the appeal, despite the rule set out in art. 340 C.C.P. that legal costs are borne by each party in family matters.

The deliberate nature of the breach is a key factor in the analysis. The appellant knew of the problem before he even filed his memorandum and took no steps whatsoever to mitigate the harm caused. The explanation he offered when questioned at the hearing, namely that he had elected not to include the disputed decisions in his book of authorities, was found to be clearly without merit. Finally, the Court notes that the appellant was not ill-equipped to deal with legal proceedings and legal argument. Working as an IT consultant for his own firm, he was also representing himself at first instance, where he demonstrated an ability to advance numerous arguments on complex issues.

Conclusion

The decision confirms what the Superior Court had stated last fall in Specter Aviation, namely that the flexibility that access to justice calls for on the part of the courts toward citizens who must represent themselves without a lawyer can never translate into “tolerance of falsehood”[5] [translation].

The Court is clear: misleading the court by deliberately supporting one’s arguments with non-existent decisions, whether generated by artificial intelligence or otherwise, amounts to a substantial breach in the conduct of the proceeding under art. 342 C.C.P. Since the opposing party will not always detect the fabrication, and since an application under art. 342 C.C.P. is less likely to be made where the parties represent themselves, we can expect that the courts will increasingly be called upon to exercise the discretion that provision confers on them to act on their own initiative.

[1] Droit de la famille — 261234, 2026 QCCA 1092 (corrected on August 18, 2026).

[2] 9401-0428 Québec Inc. v. 9414-8442 Québec Inc., 2025 QCCA 1030; 9302-5773

Québec Inc. v. West Coast Aircraft Sales and Leasing Ltd., 2023 QCCA 823, paras. 9–12.

[3] Makongo v. Montpetit, 2026 QCCQ 746.

[4]  Specter Aviation Limited v. Laprade, 2025 QCCS 3521.

[5] Ibid., para. 43.