A Montreal arbitrator tasked with resolving a dispute between a health authority and medical clinic cited nonexistant court decisions “hallucinated” by artificial intelligence, a Quebec judge has found.
Superior Court Judge Martin F. Sheenan’s April 22 ruling struck down arbitrator Michel A. Jeanniot’s August 2025 decision, which the judge said “relies on nonexistent doctrines and jurisprudence, which leads me to believe it was written with the use of artificial intelligence.”
The dispute between the clinic, Centre de Santé Osman, and the health authority, Centre intégré universitaire de santé et de services sociaux du Centre-Sud-de-l’Île-de-Montréal (CCSMTL), revolved around a $1.2-million payment the clinic said it was owed.
CCSMTL had refused to pay the bill and, when the association representing the clinic filed a dispute, argued the clinic had missed its deadline to contest the nonpayment.
The health authority argued the clinic was subject to a 90-day deadline to file a dispute, while the clinic argued provincial law overrode that deadline and allowed a three-year window.
The arbitrator sided with the health authority, citing court decisions that he said supported a shorter deadline.
But those decisions did not exist.
In his decision, Sheenan found that Jeanniot’s decision hinged entirely on nonexistent legal references, likely invented by an AI tool.
“All of the doctrinal and jurisprudential references that the arbitrator relies on are nonexistant and ‘hallucinated,’” Sheenan wrote, finding that the decision didn’t comply with Quebec law.
“The decision doesn’t respect the arbitration procedure, because the arbitrator delegated a part of his decision-making power to a generative artificial intelligence tool,” he said.
Quoting decisions from other courts, Sheenan said an arbitrator is required to undergo the decision-writing process themself, in part to favour more rigorous analysis and to reduce the risk of making an arbitrary decision.
“A growing number of legal professionals” are using artificial intelligence, the judge said, warning that such use comes with risks. “While there is nothing inherently wrong with using a reliable artificial intelligence tool, the rules impose an obligation on lawyers and parties to ensure the accuracy of their proceedings,” he said.
Sheenan also referenced Canadian Judicial Council rules, which prohibit judges from delegating decision-making powers to AI.
The Gazette has contacted Jeanniot for comment.
I’ve reported for The Gazette since 2024. I love covering a good politics story, but any day I tell Montrealers something new about the world around them feels like a good one. Got a tip for me? Email me at jawilson@postmedia.com