Mark Zuckerberg is speaking at the Viva Technology conference amid heightened concerns over how Facebook handles user data.

The social network’s co-founder and chief executive is speaking to Maurice Levy, the chairman of advertising firm Publicis.

Zuckerberg has come under criticism from politicians for his lack of answers regarding the Cambridge Analytica scandal. Facebook has admitted that the data of 87 million users may have been improperly shared with Cambridge Analytica.

Zuckerberg was grilled by U.S. and European Union lawmakers, but has denied requests to appear before U.K. parliamentarians.