Law Society of Ontario v. Lee, 2026 ONLSTH 136
·Law Society Tribunal (Ontario), Hearing Division·CASuspension
The Law Society Tribunal suspended Toronto lawyer Jisuh Lee's licence for six months and ordered CAD 10,000 in costs after she filed a factum containing AI-generated fictitious or irrelevant precedents in a family law proceeding that had become an estate matter. It follows Mazaheri (June 2026) and is reported as Ontario's first licence suspension for AI misuse.
- Court
- Law Society Tribunal (Ontario), Hearing Division
- Date
- 2026-07-16
- Who used the AI
- Lawyer
- AI tool
- Not identified in the record
- Conduct
- Toronto lawyer Mary Hyun-Sook (Jisuh) Lee relied on a factum containing AI-generated nonexistent or irrelevant case law in a 2025 family law proceeding that had become an estate matter. The tribunal stressed her lack of understanding of the technology.
- Outcome
- Suspension
- Penalty
- CA$10,000
- Regulatory outcome
- Law Society of Ontario (Law Society Tribunal): Six-month licence suspension and CAD 10,000 costs for filing a factum containing AI-generated nonexistent or irrelevant case law. (2026-07-16)
- Status
- Verified against listed sources
- Last checked
- 2026-09-05
What was fabricated or misused
- Johnson v Lanka, 2010 ONSC 4124 — factum said the court removed an estate trustee; the decision stated the opposite
- Meschino Estate v Meschino, 1998 Can LII 14734 (ONSC) — no such case exists
- Alam v Shah, 2023 ONSC 1772 — no such case exists
- DaCosta v DaCosta, 2010 ONSC 2178 — no such case exists
What the court said
“The Lawyer relied on a factum in a court proceeding she prepared with artificial intelligence (AI), which contained non-existent case law and which misrepresented what one case stood for.”
“She failed to serve her client by relying on a factum prepared by AI containing only non-existent and misrepresented case law.”
“The failure to perform legal services competently in this case lies in the Lawyer’s failure to verify the authenticity of the authorities generated by AI.”
“It is the lawyer’s duty not to fabricate case precedents and not to mis-cite cases for propositions that they do not support.”
Timeline
- Lee served and later filed a motion factum with four AI-hallucinated authorities.
- Justice Myers questioned the unlocatable cases and asked whether ChatGPT was used.
- Justice Myers ordered Lee to show cause why she should not be cited for contempt.
- Show-cause proceeding was dismissed conditionally after factum withdrawal, education and no-billing terms.
- Lee admitted to the Law Society investigator that she prepared the factum with ChatGPT.
- Tribunal held the discipline hearing by videoconference and written submissions.
- Tribunal imposed a six-month suspension and CAD 10,000 costs.
Why this case matters
Lee is the regulator-side companion to Ko v Li. The court record showed the false factum and shifting explanations; this tribunal decision supplied the professional penalty. The panel treated AI misuse and dishonesty as distinct misconduct, then accepted a joint six-month suspension after asking whether revocation or a longer suspension should be considered. Compared with Zhang v Chen, which led to personal costs and file review, Lee records a licence suspension and regulator costs in Ontario. The decision also anchors the lesson in Ontario Rule 4.06.1, which requires counsel to certify the authenticity of authorities in a factum.
Practice note
Ontario factum checks must satisfy Rule 4.06.1 before filing: every authority should be opened, matched to the citation, and checked for the proposition and pinpoint. If a judge asks whether ChatGPT or another tool was used, answer with the same account that will be given to the regulator. Blaming staff without a factual basis made the penalty worse.
Primary sources for this incident
- Lee v. Law Society of Ontario, 2026 ONLSTH 136 (CanLII; mirrored PDF of the tribunal reasons read 5 Sep 2026; CanLII blocks automated access)
- ullaw.ca (press report)
- HR Reporter (press report)
- Law Society of Ontario v Lee, 2026 ONLSTH 136 (16 July 2026), tribunal reasons (mirrored PDF; CanLII blocks automated access)
Related regulation records for this incident
No related regulation record has been linked to this incident yet.
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Cite this record
SafeLegalAI Global Legal AI Incident Tracker, “Law Society of Ontario v. Lee, 2026 ONLSTH 136”, safelegalai.com/tracker/lee-v-law-society-of-ontario (accessed 2026-10-07). Data: CC BY 4.0.