Italy’s antitrust watchdog said on Friday it had opened a probe into whether messaging service WhatsApp obliged users to agree to sharing personal data with its parent company Facebook and imposed “unfair” conditions on users.

WhatsApp fb said in August it would start sharing phone numbers with the social network, prompting European regulators to declare they would put the matter under close scrutiny.

The Italian agency said it was investigating whether the WhatsApp application had led users to believe they would have not been able to continue using it unless they agreed to terms and conditions including the sharing of personal data.

It is also looking into WhatsApp’s terms of use including only the provider having the right to terminate the agreement, and “unjustified” interruptions to service.

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The maximum fine that could be levied at the end of the investigation is 5 million euros ($5.47 million).

For more, read: EU Privacy Watchdogs Just Warned WhatApp and Yahoo Over User Data Cases

A spokeswoman for WhatsApp said the company was working with data protection authorities to address their questions.