Jean Laprade was ordered by the Superior Court of Quebec to pay $5,000 CAD (around €3,050 or £2,655) because his submissions contained “citations of authorities and case law that simply do not exist”.

Laprade, who was not represented by a lawyer, was one of four defendants in a long-running civil case brought by two aviation companies, Specter Aviation Limited and TVPX Aircraft Solutions Inc.

He apologised to the court for errors in his submissions, but said he would not have been able to defend himself without the aid of AI.

In his judgment, Judge Luc Morin said: “While access to justice requires a certain flexibility on the part of the courts when dealing with citizens who represent themselves without the assistance of a lawyer, this flexibility can never translate into tolerance of falsehoods.”

Eight instances of “non-existent citations, unissued decisions, irrelevant references, and inconsistent conclusions” were identified in the submissions.

Laprade’s reliance on “fictitious excerpts from case law and other authorities” represented a serious breach of conduct, regardless of whether it was “intentional or the result of simple negligence”, the court said.

“While the court is sensitive to the fact that Mr Laprade’s intention was to defend himself to the best of his ability by resorting to artificial intelligence, his conduct nonetheless remains highly reprehensible,” it continued.

“He must bear alone all the opprobrium resulting from citations ‘hallucinated’ by the artificial intelligence on which he relied to generate his challenge.

“A generous interpretation of his conduct leads the court to conclude that he wasted the time of several interveners, the plaintiffs’ lawyers and the court most of all.

“A more severe interpretation could have led the court to conclude that Mr Laprade knowingly attempted to mislead it, a breach that falls at the other end of the spectrum of procedural breaches.”

The court said a fine of $5,000 CAD was appropriate punishment for the procedural breach, considering “the need to deter this type of conduct”.