Facebook CEO Mark Zuckerberg is set to meet with lawmakers in Europe on Tuesday as concerns over the way his company handles its users’ data continue to pile up.

Antonio Tajani, president of the European Parliament, announced Monday that the meeting with Zuckerberg would be webcast live. It is set to be broadcast on the parliament’s website; parliamentarians had pushed for the event to be broadcast, criticizing the lack of transparency that would have accompanied a closed-door meeting.

Politicians in the U.S. and Europe are seeking answers from Facebook after it was revealed that the data of 87 million users may have been improperly shared with political data analytics firm Cambridge Analytica.

In Europe, lawmakers are set to address Facebook’s approach to privacy and data protection and how the social network could have been used as a platform for misinformation to sway the results of elections.

“I expect tough questions on Zuckerberg with regards to his data protection or non-protection regime on Facebook to explain how it’s going to prevent in the future data from simply being misused from third parties, but also how it can make sure there’s no interference in national or local decision-making, such as elections or referenda,” Ska Keller, co-president of the Greens-European Free Alliance group in the European Parliament, told CNBC’s “Squawk Box” on Tuesday.

Zuckerberg was questioned by U.S. lawmakers on Capitol Hill last month. At times, the Facebook co-founder was unable to answer questions from politicians, saying instead that his team would follow-up with them afterwards.

Udo Bullmann, chair of the Group of the Progressive Alliance of Socialists and Democrats in the European Parliament, said that Zuckerberg’s lack of answers to those questions would likely be seized upon during Tuesday’s meeting in Brussels.

“We much too often heard ‘I don’t know,'” Bullmann said. “Meanwhile, we have six weeks after the discussions with U.S. colleagues so Mark Zuckerberg should know meanwhile what happened in his corporation.”

He added: “Especially, we want to know why he did not warn customers, knowing about the malpractices since 2015. We would like to know, of course, what he changed in his business model and in the relevant technological practices to lift up to European standards and it will be a very vivid conversation.”

Facebook discovered in 2015 that information on users had been compromised as a result of data sharing with Cambridge Analytica. That data had been obtained by Cambridge Analytica via Aleksandr Kogan, a Cambridge University researcher, whose personality quiz app “This Is Your Digital Life” harvested the data of Facebook users and their friends.

A sweeping overhaul of Europe’s data protection legislation is set to come into force on Friday. The law, called the General Data Protection Regulation (GDPR), threatens to fine firms up to 4 percent of annual global turnover or 20 million euros ($23.6 million), whichever is the highest amount.

The regulation aims to take control over data from businesses and place it in the hands of consumers. Once implemented, it will let people force firms to delete data on them and will make it compulsory for companies to notify authorities about data breaches within 72 hours of first becoming aware of it.

In an emailed statement Monday, a spokesperson for Facebook said the company was “looking forward to the meeting and happy for it to be livestreamed.”