ROME - Italy's data protection agency announced on Friday that it has fined artificial intelligence company OpenAI 15 million euros (about $15.6 million) and mandated a public information campaign.

The decision follows a 21-month investigation into the privacy and data management practices of the US-based company, which operates the ChatGPT service.

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The investigation alleged that OpenAI used users' personal data to train its ChatGPT chatbot "without having adequate legal basis" and failed to uphold the principle of transparency. It also concluded that the company provided insufficient mechanisms for age verification, potentially exposing children under 13 to inappropriate responses.

In addition to the fine, OpenAI has been ordered to launch a six-month media campaign in Italy to raise public awareness about its services and data collection practices.

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OpenAI criticized the decision, calling it "unreasonable", and announced plans to appeal.