Skip to main content
NOPE
Low reported severity Regulatory Action

Czech Constitutional Court fines a lawyer 25,000 crowns over a complaint citing non-existent rulings; the lawyer says a paid legal AI tool drafted it

On 1 December 2025 the presiding judge of a chamber of the Czech Constitutional Court fined a Prague lawyer 25,000 crowns (a quarter of the statutory maximum) for grossly obstructing proceedings. The lawyer had filed a constitutional complaint, for a client refused a temporary residence permit, that argued from 12 decisions of the Constitutional Court and the European Court of Human Rights; the court found that a substantial part of them did not exist and part were grossly misinterpreted. The order says the complaint showed signs of generative AI and that the court presumed the lawyer had generated it with an AI model and then failed to verify the citations. The lawyer confirmed to INFO.CZ that an AI tool was used, described it as a paid professional model from a legal information system provider, said the output was not checked enough, and expressed regret. The court invited the client to correct the complaint so that the client would suffer no procedural harm; the complaint was later rejected as manifestly unfounded on 30 January 2026. INFO.CZ reported on 10 December 2025 that the lawyer had apologised and paid the fine and that the Czech Bar Association's supervisory board was examining the case.

AI system
Unidentified legal research tool
Occurred
1 Dec 2025
Reported
3 December 2025
Event location
Czechia
What the AI did
Communicated with the person · Informed a human decision about the person
Reported harm
Financial LossLegal Harm
Whose AI use
Their own AI use
Setting
Justice · Work
Evidence
AI involvement supported · Causal attribution established · 5 sources
7 claims: 4 documented, 3 reported. 3 open questions
People reported harmed
1 person

AI system as recorded: A paid professional AI model offered by a legal information system provider, used to draft a constitutional complaint (provider not named; the court inferred generative AI from the text and the lawyer confirmed its use)

What Happened

The complaint. A Prague lawyer filed a constitutional complaint for a client whose application for a temporary residence permit had been refused and whose court challenges had failed. According to the Constitutional Court's order of 1 December 2025, the complaint argued from 12 decisions of the Constitutional Court and the European Court of Human Rights; after careful study the court found that a substantial part of them did not exist and part were grossly misinterpreted, and that the number and nature of the defects ruled out isolated typing errors.

The AI finding. The order says the complaint also showed signs of AI use (an anglicism, incomplete note-like sentences, inconsistent citation formats, failure to distinguish a judgment from a resolution), which led the court to presume that the lawyer had generated the filing with an AI model and then had not verified the citations or the argument. The court said it does not matter which people or tools lawyers use, but that as legal professionals they take full responsibility for a filing, including any hallucinated AI argument.

The fine. Finding that the lawyer had misled the court and needlessly complicated and delayed its proceedings, the presiding judge imposed a disciplinary fine of 25,000 crowns, a quarter of the statutory range, because it was a first failing and the defect could still be remedied. In parallel the court invited the client to remedy the complaint so that the client would not suffer procedural harm. INFO.CZ described the fine as probably the first of its kind from the Constitutional Court.

The lawyer's account. The lawyer confirmed to INFO.CZ that AI had been used to write the complaint, expressed regret, said the tool was used because the lawyer rarely appears before the Constitutional Court and was under time pressure, and admitted the mistake was not checking the output enough. INFO.CZ reports that the tool was a paid professional AI model offered by a large legal information system provider, which the lawyer declined to name, and quotes the lawyer as saying the contract with that provider would not be renewed.

Afterwards. INFO.CZ reported on 10 December 2025 that the lawyer had apologised to the court and paid the fine, and that, according to its sources, the Czech Bar Association's supervisory board was examining the case; the bar's president said that using AI for a filing without checking sources may be a disciplinary offence, while the bar expressed reservations about courts fining lawyers for filings they judge to be of poor quality. Advokatni denik (ČTK) reported that the court appreciated that the lawyer paid the fine promptly and apologised. The court rejected the complaint as manifestly unfounded on 30 January 2026; that resolution does not mention AI.

Reported harm

According to the Constitutional Court's order, a lawyer whose complaint cited non-existent and misinterpreted rulings, which the court presumed were AI-generated and the lawyer says came from a paid legal AI tool, was fined 25,000 crowns; INFO.CZ reported that the bar association's supervisory board was examining the case.

Outcome

Resolved

Constitutional Court order I. US 3004/25 of 1 December 2025: disciplinary fine of 25,000 crowns under section 61(1) of the Constitutional Court Act, set at a quarter of the maximum because it was the lawyer's first such failing and the defect could still be remedied; no appeal lies against the order. The client was invited in parallel to remedy the complaint. On 30 January 2026 the court rejected the complaint as manifestly unfounded, on its merits as set out in that resolution. INFO.CZ (10 December 2025) reported that the lawyer had apologised and paid the fine and, citing its own sources, that the Czech Bar Association's supervisory board was examining the case; no outcome of that examination was found.

What remains unknown

  • The name of the AI tool and its provider; the lawyer declined to name it.
  • The date the complaint was filed (INFO.CZ says it reached the court in October 2025).
  • The outcome of the Czech Bar Association supervisory board's examination, if any.

What the evidence supports

AI involvement: supported. The Constitutional Court's order finds that a substantial part of the 12 decisions cited in the complaint did not exist, identifies signs of AI-generated text, and presumes the lawyer generated the filing with an AI model without verifying it; the lawyer confirmed to INFO.CZ that an AI tool, a paid professional model from a legal information system provider, was used and that its output was not checked enough. The tool's output reached the lawyer and went into the complaint (communicated_with), and the court read those invented authorities and fined the lawyer for them (informed_decision_about). The provider is not named.

7 claims: 4 documented, 3 reported. What the statuses mean

Documented On 1 December 2025 the presiding judge of a Constitutional Court chamber fined the lawyer 25,000 crowns for grossly obstructing proceedings, at a quarter of the statutory range because it was a first failing and the defect could still be remedied.

Causal attribution. The fine responded to the filing; the order attributes the defects to the lawyer's failure to verify presumed AI output.

  • nalus.usoud.cz(opens in new tab) supports · Czech
    I.ÚS 3004/25 ze dne 1. 12. 2025; jako povinnému se ukládá pořádková pokuta ve výši 25 000 Kč; Pokutu uložil pouze ve čtvrtině zákonného rozpětí, neboť se povinný hrubého ztížení postupu řízení před Ústavním soudem dopustil poprvé a vadu podání lze ještě odstranit.
Documented The complaint argued from 12 decisions of the Constitutional Court and the European Court of Human Rights, a substantial part of which did not exist and part of which were grossly misinterpreted.

Causal attribution. Established by the court's own verification.

  • nalus.usoud.cz(opens in new tab) supports · Czech
    V ústavní stížnosti argumentoval celkem 12 rozhodnutími Ústavního soudu a Evropského soudu pro lidská práva. Po pečlivém prostudování ústavní stížnosti Ústavní soud zjistil, že podstatná část z těchto rozhodnutí vůbec neexistuje a část je povinným hrubě dezinterpretována.
Documented The court found signs of AI use in the complaint and presumed that the lawyer had generated it with an AI model and then failed to verify the citations and argument.

Causal attribution. The order records the court's presumption of AI generation; the lawyer's confirmation is a separate claim (c4).

  • nalus.usoud.cz(opens in new tab) supports · Czech
    To vede Ústavní soud k domněnce, že povinný generoval podání pomocí některého z modelů umělé inteligence, poté však neověřil existenci citovaných rozhodnutí a správnost argumentace, resp. citace.
Reported The lawyer confirmed to INFO.CZ that AI was used to write the complaint, said the output was not checked enough, and described the tool as a paid professional AI model from a large legal information system provider.

Causal attribution. The lawyer attributes the false citations to the AI tool's output that was not checked.

  • info.cz(opens in new tab) supports · Czech
    Že opravdu použil při sepisování stížnosti umělou inteligenci, potvrdil INFO.CZ samotný advokát, který nad celou situací vyjádřil lítost.; Přiznává, že jeho chybou bylo, že výstup nedostatečně kontroloval a spolehl se na to, že uvedená judikatura odpovídá.; placený profesionální model AI, který nabízí některá z velkých společností provozujících komplexní právní informační systémy
Documented The court invited the client to remedy the complaint so that the client would suffer no procedural harm, and later rejected the complaint as manifestly unfounded on 30 January 2026.

Causal attribution. No source connects the rejection to the AI-generated citations.

  • nalus.usoud.cz(opens in new tab) supports · Czech
    Stěžovateli, prostřednictvím jeho právního zástupce, souběžně Ústavní soud zasílá výzvu k odstranění vad ústavní stížnosti, aby stěžovatel v důsledku postupu svého právního zástupce neutrpěl procesní újmu.
  • nalus.usoud.cz(opens in new tab) supports · Czech
    I.ÚS 3004/25 ze dne 30. 1. 2026; Ústavní stížnost se odmítá.
Reported The lawyer apologised and paid the fine, and the Czech Bar Association's supervisory board was reported to be examining the case.

Causal attribution. Consequence of the fine; the bar examination rests on INFO.CZ's unnamed sources.

  • info.cz(opens in new tab) supports · Czech
    Podle zdrojů INFO.CZ se kontrolní rada ČAK tímto konkrétním případem již zabývá. A to přestože se advokát soudu omluvil, pokutu zaplatil a klienta se jeho selhání nedotkne, neboť od ÚS dostal prostor na nápravu.
  • advokatnidenik.cz(opens in new tab) supports · Czech
    Ústavní soud ocenil následný přístup advokáta, který pokutu obratem uhradil a zaslal omluvu.
Reported The Czech Bar Association's president said using AI for a filing without checking sources may be a disciplinary offence, while the bar expressed reservations about courts fining lawyers for filings they judge to be of poor quality.

Causal attribution. Context and a qualification of the sanction, not a causal claim.

  • info.cz(opens in new tab) supports · Czech
    Pokud jde o využití AI pro přípravu podání bez kontroly zdrojů, může se skutečně jednat o kárné provinění advokáta; Ve svých důsledcích by to mohlo vést k postihování advokáta obecně za podání, které soud vyhodnotí jako nekvalitní nebo s nesprávně aplikovanou judikaturou

Sources

5 sources inspected. Sources that repeat one account do not corroborate each other.

How the sources were read, and where the events happened

Read in Czech on 2026-10-26 (HTTP 200); quoted passages were translated by the research agent (an AI). Order dated 1 December 2025 in the NALUS database; the client and lawyer are named in the order and are not reproduced here. Applies to s1.

Read in Czech on 2026-10-26 (HTTP 200); quoted passages were translated by the research agent (an AI). Resolution dated 30 January 2026 in the NALUS database. Applies to s2.

Read in Czech on 2026-10-26 (HTTP 200); quoted passages were translated by the research agent (an AI). INFO.CZ broke the story and interviewed the fined lawyer; later reports relay its interview. Applies to s3.

Read in Czech on 2026-10-26 (HTTP 200); quoted passages were translated by the research agent (an AI). Follow-up article with statements of the Czech Bar Association president and the presidents of the two top courts. Applies to s4.

Read in Czech on 2026-10-26 (HTTP 200); quoted passages were translated by the research agent (an AI). Bar Association journal article credited to the ČTK news agency. Applies to s5.

Event countries: Czechia. Affected-person countries: Unknown. Court countries: Czechia.

The complaint was filed with, and the fine imposed by, the Czech Constitutional Court; the reports describe the lawyer as practising in Prague. Residence is not recorded as a country of the affected person.

Reviewed for publication 2026-10-26: Published as a concrete adverse consequence of AI use: the Constitutional Court's order fines a lawyer for a complaint whose non-existent citations it presumes were generated with an AI model, and the lawyer confirmed using a paid legal AI tool without checking its output.

People described

A Prague lawyer who filed a constitutional complaint drafted with an AI tool and was fined for its non-existent citations

People reported harmed in this case

1 person

1 AI participant · 0 other people harmed

One person: the lawyer fined by the Constitutional Court. The court invited the client to remedy the complaint so that the client would suffer no procedural harm, and INFO.CZ reports that the client was not affected, so the client is not counted.

Counted once within this case. The same person may appear in other cases. This count does not establish AI causation.

Tags

#czechia#legal-profession#hallucinated-citations#court-fine#constitutional-court

Cite this case

Compiled per our published methodology: verification statuses, sourcing standards, and corrections process.

APA

NOPE. (2026). Czech Constitutional Court fines a lawyer 25,000 crowns over a complaint citing non-existent rulings; the lawyer says a paid legal AI tool drafted it. AI incidents. https://nope.net/incidents/2025-czech-constitutional-court-fines-lawyer-for-complaint-citing-non-existent-rulings-drafted-with-ai-tool

BibTeX

@misc{2025_czech_constitutional_court_fines_lawyer_for_complaint_citing_non_existent_rulings_drafted_with_ai_tool,
  title = {Czech Constitutional Court fines a lawyer 25,000 crowns over a complaint citing non-existent rulings; the lawyer says a paid legal AI tool drafted it},
  author = {NOPE},
  year = {2026},
  howpublished = {AI incidents},
  url = {https://nope.net/incidents/2025-czech-constitutional-court-fines-lawyer-for-complaint-citing-non-existent-rulings-drafted-with-ai-tool}
}

Related cases

Low Unidentified legal research tool

Russian intellectual property court fined an Udmurtia entrepreneur 5,000 roubles over non-existent case law he said an AI service selected, reports say

Russia's Court for Intellectual Property Rights fined an individual entrepreneur from Udmurtia 5,000 roubles for contempt of court after finding that part of the 12 references to case law in his cassation appeal, including one said to be a Supreme Court position, pointed to court acts that do not exist or attributed conclusions to them, the court's press service told RIA Novosti on 27 August 2026. Rossiyskaya Gazeta reports that the entrepreneur explained he had prepared the appeal with an AI-based service that selected the case law, and that his side argued he had no legal education and could not check the references; the court rejected the argument that the errors were technical. The date of the ruling and the AI service are not reported.

Low Unidentified legal research tool (suspected)

Puerto Rico federal judge sanctions a soccer league's lawyers over 55 defective citations he said bore hallmarks of generative AI; the lawyers deny using AI

In an antitrust lawsuit that the Puerto Rico Soccer League brought against FIFA, CONCACAF and Puerto Rican football officials, Chief U.S. District Judge Raúl Arias-Marxuach found dozens of inaccurate or nonexistent legal citations across four filings by the league's two attorneys. According to Law Commentary, he said the errors bore hallmarks of generative AI and found that the lawyers violated Rule 11 by failing to reasonably verify the authorities they cited. Lawyer Monthly reports that the sanctions were decided in April 2025 and that an order of 23 September 2025 set the penalty at $24,492.10, payable to FIFA and the other defendants. Both lawyers have denied using artificial intelligence. In an October 2026 filing FIFA asked the court to dismiss the league's remaining claim because the sanction had not been paid. The lawyers proposed paying $1,000 a month, cited financial difficulties and an injury one of them suffered in March 2026, and argued that dismissal would punish their client for penalties imposed on them personally. The court had not ruled on the dismissal request when these reports were published.

Medium Unidentified AI research tool

Alabama Supreme Court dismisses two siblings' family-trust appeal as a sanction after their lawyer admits using AI that produced fake citations

On 24 April 2026 the Supreme Court of Alabama dismissed an appeal by two siblings in a family dispute over living trusts because their lawyer, W. Perry Hall, had filed briefs in which most of the legal authorities were misquoted or did not exist. The court said they appeared to be AI hallucinations, and at a show-cause hearing in February 2026 Hall admitted that many authorities did not exist and that he had improperly used AI to obtain them. The court ordered Hall to pay the opposing party's fees and costs of $17,200 and double appeal costs, barred him from filing in the court without a co-signing attorney and referred him to the Alabama State Bar. It said the dismissal was imposed as a sanction because of the particularly egregious facts. One justice, concurring in part and dissenting in part, objected to dismissing the appeal as a sanction for the lawyer's conduct but would have affirmed the judgment against the clients on the merits.

Medium vLex, Paxton AI and NotebookLM (reported)

New York federal court enters default judgment against a defendant and orders its lawyer to pay $38,877 after false citations it found AI produced

In a federal trademark suit in the U.S. District Court for the Southern District of New York, the court on 5 February 2026 struck a company defendant's motion papers and entered default judgment against it as a sanction on its lawyer, after his filings repeatedly cited nonexistent cases and misattributed quotations. The lawyer said he had found and cite-checked cases with AI tools (vLex and Paxton AI) and used NotebookLM to review a later submission; the court rejected his explanations and found he acted in bad faith. On 9 October 2026 the court described the citations as produced by generative AI and ordered the lawyer to pay $38,877.59 in fees and costs to the firm of a co-defendant's former lawyer, who had reported the false citations to the court.

If you or someone you know is struggling, free and confidential support is available. Find a helpline near you at Signpost.

Back to all incidents