Sanction teardown · C.D. California, USA · 2025-09-12
Yi-Sheng Fang, et al. v. Hechalou US LLC, et al.
What happened
In C.D. California, USA, a filing relied on an unnamed/unconfirmed AI tool to help draft legal argument. The court identified the following problems with the citations in that filing:
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Fabricated (Case Law)Opposition cited cases that do not exist; Plaintiffs' supplemental declaration identified multiple non-existent cases attributed to AI generation.
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False Quotes (Case Law)Opposition included quotations that do not appear in the cited authorities; Notice of Errata flagged four such nonexistent quotations and Plaintiffs identified additional misquotes.
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Misrepresented (Case Law)Some cited cases exist but do not contain the quoted language or address the points asserted — the authorities were misrepresented and did not support the proffered propositions.
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Fabricated (Case Law)Citations to cases that do not exist (AI-generated, non-existent authorities identified by Plaintiffs).
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False Quotes (Case Law)Quotations attributed to existing cases that did not contain the quoted language (false quotations identified by Plaintiffs).
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Misrepresented (Case Law)Citations to existing cases that do not address the point argued (misrepresentation of precedent).
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Misrepresented (Case Law)Two instances where case citations were changed for the proffered proposition (mis-citation/misrepresentation).
Which AI tool
an unnamed/unconfirmed AI tool. 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
Monetary sanction; Order to notify State Bar and compliance declaration (monetary penalty: 2418 USD.)
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.
Check a brief before you file it → · See our live false-verify rate
Source: https://www.damiencharlotin.com/documents/795/Yi-Sheng_Fang_et_al._v._Hechalou_US_LLC.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).