Mazurek et al. v. Thomazoni
Parana State · Apr 2, 2025
What happened in this matter?
The court sanctioned the attorney for litigation in bad faith due to the submission of fabricated AI-generated case law. The court imposed a monetary fine of 1% of the case value and referred the matter to the Brazilian Bar Association (OAB) for disciplinary investigation into the attorney's professional conduct.
- Why the court cared
- The court reasoned that the attorney's failure to verify the existence of cited jurisprudence, despite the availability of court records, constituted temerarious conduct and litigation in bad faith under the Brazilian Code of Civil Procedure. The court emphasized that while AI tools may assist in research, they do not replace the lawyer's professional duty of care and supervision.
- Why it matters now
- ChatGPT-generated TJPR citations with retired judges are easily detected—verify relator chamber and tenure before filing.
Why this matter is tracked
In an inheritance dispute, the appellants' counsel submitted multiple fabricated TJPR appeal decisions generated by ChatGPT. The court determined that the counsel failed to exercise the required professional duty of care by not verifying the existence or accuracy of the cited jurisprudence. The court affirmed the lower court's decision regarding the inheritance order and sanctioned the attorney for litigation in bad faith. The court imposed a monetary fine of 1% of the updated case value and ordered the issuance of an official notice to the Brazilian Bar Association (OAB) to investigate the attorney's professional conduct regarding the use of AI and the submission of non-existent case law.
ChatGPT-generated TJPR citations with retired judges are easily detected—verify relator chamber and tenure before filing.
Record details
What the record establishes about AI use
The attorney admitted to using ChatGPT for research.
Appellate review of an interlocutory appeal (Agravo de Instrumento) in a probate/inheritance action.
Correction behavior is not separately verified in the current record.
Tracked discrepancy record
3 citation, quotation, or authority issues are recorded in the source dataset.
- Fabricated: Case Law | Fabricated TJPR appeal decision; not found in Projudi; attributed to a retired judge who never sat on the 8th Chamber.
- Fabricated: Case Law | Fabricated TJPR agravo de instrumento; not found in Projudi; numbering pattern incompatible; attributed to a judge retired since 30/01/2023 but allegedly judged in 2024.
- Fabricated: Case Law | Fabricated TJPR appeal decision; not found in Projudi; relator indicado pertence à 11ª Câmara desde 2010, não à 7ª Câmara informada.
Questions this record answers
- What happened in Mazurek et al. v. Thomazoni?
- The court sanctioned the attorney for litigation in bad faith due to the submission of fabricated AI-generated case law. The court imposed a monetary fine of 1% of the case value and referred the matter to the Brazilian Bar Association (OAB) for disciplinary investigation into the attorney's professional conduct.
- Why does Mazurek et al. v. Thomazoni matter for legal AI risk?
- ChatGPT-generated TJPR citations with retired judges are easily detected—verify relator chamber and tenure before filing.
- What does the public record establish about Mazurek et al. v. Thomazoni?
- The record summarizes the outcome described in the linked public source. The recorded document is hosted in the upstream publisher archive. This page is not a substitute for the complete docket, subsequent history, or jurisdiction-specific advice.
- Which source supports this Mazurek et al. v. Thomazoni summary?
- The recorded source is Damien Charlotin case archive. It is classified as publisher document archive; review the linked material and subsequent docket history before relying on this summary.
Related matters
Related by court, jurisdiction, tool, or classified failure pattern. Similarity does not imply the same facts or outcome.