ChatGPT, the artificial intelligence-powered chatbot, breaches rules on data protection, an Italian watchdog says.
An inquiry by Italy's Data Protection Authority (DPA) found data privacy violations, which the BBC understands are related to collecting personal data and age protections.
The chatbot relies on being fed large amounts of data from the internet.
ChatGPT's maker OpenAI told the BBC it believed its practices "aligned" with privacy laws.
"We want our AI to learn about the world, not about private individuals", it said in a statement.
"We actively work to reduce personal data in training our systems like ChatGPT, which also rejects requests for private or sensitive information about people".
It has 30 days to respond with its defence.
Italy has taken a firm stance on data protection when it comes to ChatGPT.
It was the first Western country to block the product in March 2023, citing privacy concerns.
ChatGPT was reinstated around four weeks later, after stating it had successfully "addressed or clarified" the issues raised by the DPA.
Italy's DPA launched a "fact-finding activity" at the time, which it says has now found data privacy violations.
In a statement, the DPA said it "concluded that the available evidence pointed to the existence of breaches of the provisions contained in the EU GDPR [General Data Protection Regulation]".
They are related to mass collection of users' data which is then used to train the algorithm.
The regulator is also concerned that younger users may be exposed to inappropriate content generated by the chatbot.
Under the EU's GDPR law, firms which break the rules can be fined up to 4% of the company's global turnover.
Italy's DPA works alongside the European Union's European Data Protection Board - which set up a special task force to monitor ChatGPT in April 2023.
At the time of ChatGPT's reinstatement in Italy in April 2023, the Italian regulator told the BBC that it "welcomed the measures OpenAI implemented" but called for even more compliance.
In particular, a spokesperson said, it wanted more action around "implementing an age verification system and planning and conducting an information campaign to inform Italians of what happened as well as of their right to opt-out from the processing of their personal data for training algorithms".
An OpenAI spokesperson said at the time that it would continue talks with the regulator.
OpenAI has close links with tech giant Microsoft, which has invested billions of dollars into the company.
Microsoft has integrated AI into its Bing search engine, as well as its Office 365 apps such as Word, Teams and Outlook.
Additional reporting by Thomas Fabbri.