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Lessard c. Longuépée

Court
Québec
Jurisdiction
Canada
Decided
2025-11-26
AI tool
ChatGPT
Outcome
Warning
Monetary penalty
None reported

What was hallucinated

Fabricated: Case Law | Plaintiff submitted 'Leblanc c. Lacasse, C.Q. 2005' from ChatGPT; court found no such decision exists and the AI reference was fabricated. || Fabricated: Case Law | Plaintiff submitted 'Girard c. Roy, 2012 QCCQ 7854' from ChatGPT; court found the referenced neutral citation points to an unrelated judgment and the cited decision does not exist as described. || Fabricated: Case Law | Plaintiff submitted 'Beaulieu c. Ferland, 2009 QCCQ 3249' from ChatGPT; court found this decision to be nonexistent and the citation corresponded to an unrelated case. || Fabricated: Case Law | Plaintiff submitted 'Bujold c. Élevage du Nord, 2018 QCCQ 1649' from ChatGPT; court determined the decision was AI-generated and the neutral citation cited was to an unrelated judgment.

Sanction teardown · Québec, Canada · 2025-11-26

Lessard c. Longuépée

What happened

In Québec, Canada, a filing relied on ChatGPT to help draft legal argument. The court identified the following problems with the citations in that filing:

  • Fabricated (Case Law)
    Plaintiff submitted 'Leblanc c. Lacasse, C.Q. 2005' from ChatGPT; court found no such decision exists and the AI reference was fabricated.
  • Fabricated (Case Law)
    Plaintiff submitted 'Girard c. Roy, 2012 QCCQ 7854' from ChatGPT; court found the referenced neutral citation points to an unrelated judgment and the cited decision does not exist as described.
  • Fabricated (Case Law)
    Plaintiff submitted 'Beaulieu c. Ferland, 2009 QCCQ 3249' from ChatGPT; court found this decision to be nonexistent and the citation corresponded to an unrelated case.
  • Fabricated (Case Law)
    Plaintiff submitted 'Bujold c. Élevage du Nord, 2018 QCCQ 1649' from ChatGPT; court determined the decision was AI-generated and the neutral citation cited was to an unrelated judgment.

Which AI tool

ChatGPT. Note: Charlotin's public database records tool attribution only where a court order, brief, or reporting on the matter states it explicitly; "unidentified" or "implied" means the record indicates AI use but does not name a specific product — we do not guess.

Outcome

Warning

How Citation Safe would have caught this

Citation Safe runs three deterministic layers before a brief is filed: (1) does the citation exist against CourtListener's database of published opinions, (2) if quoted, does that exact language appear in the source, (3) does the cited case actually support the proposition it is cited for. Fabricated case citations fail Layer 1. Fabricated or misattributed quotations fail Layer 2 even when the underlying case is real. Misrepresented holdings — a real case cited for a proposition it does not support — are the target of Layer 3. None of these checks involve asking another language model whether the citation looks right; they are lookups and text-matches against the actual source, which is why a hallucinated citation has to survive a direct lookup against the authoritative source — not another model's opinion — to earn a VERIFIED stamp; our measured false-verify rate is published live at /quality.

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Source: https://www.damiencharlotin.com/documents/1286/Lessard_v._Longu%C3%A9p%C3%A9e_Canada_26_November_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

Source: https://www.damiencharlotin.com/documents/1286/Lessard_v._Longu%C3%A9p%C3%A9e_Canada_26_November_2025.pdf

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