The US capital has sued Facebook for sharing users' data with Cambridge Analytica. It is the first legal case against Facebook over the privacy scandal.
The attorney general of Washington, DC, filed a suit against Facebook on Wednesday for allowing Cambridge Analytica to access the personal data of residents of the US capital.
Facebook earlier this year admitted that a third-party personality quiz app collected the personal information of users' friends, and the information was sold to the London-based political consulting firm Cambridge Analytica. Some 87 million users worldwide were affected.
In Washington, more than 340,000 residents were impacted but only 860 took the quiz, DC Attorney General Karl Racine said.
The lawsuit alleges Facebook knew in 2014 that the app was collecting information on users' friends but failed "to monitor or audit the app."
"We're seeking to hold Facebook accountable for jeopardizing and exposing the personal information of tens of millions of its users," Racine said. "We hope this lawsuit will ensure Facebook takes better care with its data."