Facebook members can discover whether they are among the 87 million potential users whose data was shared with Cambridge Analytica.
Every account holder is being sent one of two notices informing them whether their data was breached.
The tech giant said people will also be shown what apps they use and what data those apps may have gathered.
Facebook has additionally suspended a data analytics firm called Cubeyou, ahead of an investigation.
The tech giant will look into whether Cubeyou collected data for academic purposes and then used it commercially, following a partnership with Cambridge University in the UK.
Cubeyou denies the allegations.
The investigation follows allegations reported by CNBC, regarding a personality quiz called "You Are What You Like", which the University says was later replaced by a separate app called "Apply Magic Sauce".
However, the website from the original quiz redirected users to the new one without any clear explanation that it was a different product, with different terms and conditions.
Both the firm and Cambridge University state that the You Are What You Like app made it clear that data was for use in both academic and business purposes.
In an emailed statement received by Bloomberg, Ime Archibong, Facebook's vice-president of product partnerships, said Cubeyou's apps would all be banned from the platform if the data firm "refuses or fails" the audit.
Cubeyou said it has always complied with Facebook's rules.
The news comes as Facebook chief Mark Zuckerberg revealed how he plans to begin two days of testimony to Congress in Washington regarding the recent scandals.
His opening remarks include a pledge to never let advertisers or developers "take priority over" his firm's mission to connect people.
The You Are What You Like website was created by Cubeyou in partnership with Cambridge University's Psychometric Centre.
The university said that those who took part would have consented to their data being used "for both academic and business purposes" as it was written in the terms and conditions on the site - and added that all data was anonymised.
However, on the current terms and conditions for Apply Magic Sauce, the university states that the site may only be used for "non-profit academic research".
The university says that Apply Magic Sauce is a separate product which Cubeyou had no access to.
"Cubeyou merely designed the interface for a website that used our models to give users insight on their data," the university said.
"We have had no contact with Cubeyou since June 2015."
The University was also implicated in the Cambridge Analytica scandal, as one of its academics developed the quiz which harvested the data that was acquired by Cambridge Analytica's possession.
Cambridge University denied working with Cambridge Analytica or its parent company SCL and said it had never provided any data, algorithms or expertise.
What is Cubeyou?
It is one of a number of firms set up to help businesses such as publishers and advertisers target their marketing. It is unknown whether it has also helped campaigns spread political messages, as was the case with Cambridge Analytica.
On its website, data firm Cubeyou describes itself has having "all the best consumer data sources in one place".
"Identify consumers not only by their demographics or consumption habits but by leveraging the whole spectrum of their personalities, interests and passions," it says.
Other Facebook developments include:
- Apple co-founder Steve Wozniak told USA Today that he was leaving Facebook as he was concerned about the way many tech firms make money from personal data
- Facebook confirmed that it was working on a feature that would enable users to delete messages they had already sent from the inbox of the recipients. However, the firm told The Verge news site that it "may take some time". It followed news that messages from Mark Zuckerberg had been "unsent" in this way
What can I do?
If you have yet to receive one of the notices, Facebook has also provided a tool to check if your information could have been shared with Cambridge Analytica.
Facebook stopped letting third-party apps examine the likes, status updates and other information shared by users' friends in 2015 - so, if you are worried about developers you have never heard of profiling you, that should already have been tackled.
In addition, over the past couple of weeks, the social network has taken further steps to limit what can be learned from app users themselves, including making their religious and political views out-of-bounds.
Clicking into Facebook's search box reveals the option to delete records of individual past queries or, alternatively, all previous entries in one go.
Users can also delve into the app's settings menu to see exactly what apps they use and what data they are sharing - although they may wish to wait a little while, as the firm has promised to revamp the tools soon.
In addition, they can take advantage of the platform's archive tool, which allows them to download a copy of all the messages, photos and other personal information that they have posted to the service. Just bear in mind, it does not include data others may have posted about them or information acquired from third-party companies to fine-tune ad targeting.
Finally there's the nuclear option: the ability to delete an account via the settings menu.
Update 10 April 2018: This story has been amended, following updated information supplied by Cambridge University, that the two apps, You Are What You Like and Apply Magic Sauce, are two separate products, despite web traffic from the former being automatically redirected to the latter.
The University agreed to add a note to the You Are What You Like website to clarify the situation.