If you use Facebook, you’re probably well aware that it’s collecting information about you. But did you know that this information also includes details of your physiognomy, such as the distance between your eyebrows, the width of your smile and more? Facebook user and Illinois resident Nimesh Patel found this far too invasive and filed a class-action lawsuit against the social media company.

According to an IEEE Spectrum report, the lawsuit alleges that Facebook’s face recognition technology violates the state’s Biometric Information Privacy Act (BIPA). The legislation, which was passed in Illinois in 2008, limits how companies can both store and use people’s biometric identifiers, such as fingerprints, voiceprints, retina or iris scans and scans of hand or face geometry. It requires a written policy informing users how long they will retain this information and when it will be destroyed. Facebook doesn’t have this policy in place, therefore, according to the lawsuit, they’ve violated state law. Facebook is not alone — Google and Snapchat are also facing similar lawsuits in Illinois.

The report details that the law predates Facebook’s photo-tagging ability, which it introduced in 2010. Interestingly, Facebook turned off this feature in Europe in 2012 after privacy concerns were raised.

In 2015, Facebook filed a motion to dismiss based on its own interpretation of BIPA’s biometric identifiers, which excludes photographs and physical descriptions. The court disagreed, saying that the law also includes emerging technologies, and allowed the case to proceed. The trial will begin this October and will potentially reveal the technical aspects of Facebook’s face recognition technology.

And if Patel’s class-action is successful? Facebook will have to pay damages to millions of users in Illinois and change its policy in the state and, potentially, across the country.