Sanction teardown · Ústavní soud, Czech Republic · 2025-12-01

I.ÚS 3004/25

What happened

In Ústavní soud, Czech Republic, 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:

• Fabricated (Case Law)
  Court found 'nález' sp. zn. III. ÚS 3881/18 does not exist; cited as supporting the same line of argument.
• Fabricated (Case Law)
  Cited ECHR decision 'Stefan v. Rumunsko, č. st. 57001/10, § 36' was not found in HUDOC with that application number/paragraph and appears inaccurately cited.
• Fabricated (Case Law)
  Court found 'nález' sp. zn. III. ÚS 2987/18 does not exist; it was cited as supporting that 'mechanické užití § 104a je protiústavní'.
• Misrepresented (Case Law)
  Citation II. ÚS 2264/14 was cited as a 'nález' supporting the claimed conclusion, but under that file number only an unrelated usnesení rejecting a complaint for lack of counsel exists.
• Fabricated (Case Law)
  Court found no 'nález' sp. zn. III. ÚS 433/17; thus it could not have held that 'odmítnutí kasační stížnosti nesmí vést k formálnímu znemožnění přezkumu důležitých otázek'.
• Misrepresented (Case Law)
  Lawyer claimed Pl. ÚS 17/10 'výslovně varoval před užitím nepravomocných trestních stíhání...', but the Court found the cited decision contains no such express warning.

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 Fine (monetary penalty: 25000 .)

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/2033/NALUS_-_datab%C3%A1ze_rozhodnut%C3%AD_%C3%9Astavn%C3%ADho_soudu.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).