After Facebook received a $644,000 (£500,000) from U.K. watchdog body over its failure to keep data analytics firm Cambridge Analytica from improperly accessing user data, the company today filed a motion to appeal the fine. The BBC first reported on the news.

Facebook is appealing the fine on the grounds that an investigation from the Information Commissioner’s Office did not find any evidence that Cambridge Analytica improperly utilized the user data when targeting ads in the lead-up to the 2016 Brexit referendum.

Facebook initially estimated in March that the personal data from up to 1.1 million U.K citizens could have been accessed by Cambridge Analytica. That’s when the news broke that Facebook had failed to stop Cambridge Analytica — which claimed to work with the Leave.EU group, then retracted that claim — from getting access to user data obtained through a personality quiz and not getting their consent to use it for ad targeting.

“The ICO’s investigation stemmed from concerns that UK citizens’ data may have been impacted by Cambridge Analytica, yet they now have confirmed that they have found no evidence to suggest that information of Facebook users in the UK was ever shared by Dr Kogan with Cambridge Analytica, or used by its affiliates in the Brexit referendum,” a statement provided to the BBC from Facebook’s lawyer Anna Benckert read.

“Therefore, the core of the ICO’s argument no longer relates to the events involving Cambridge Analytica. Instead, their reasoning challenges some of the basic principles of how people should be allowed to share information online, with implications which go far beyond just Facebook, which is why we have chosen to appeal.”

However, the report did argue that Facebook was still subject to a fine because it “failed to take appropriate technical and organizational measures against unauthorised or unlawful processing of personal data,” and that U.K. residents were put at risk by Facebook’s carelessness.

The £500,000 fine was the maximum fine that the ICO could levy at the time. However, under the new GDPR rules, Facebook could have been fined up to 4 percent of Facebook’s global turnover.

VentureBeat has reached out to Facebook for more details, and will update this story if we hear back.