Facebook boss Mark Zuckerberg is expected Tuesday at the European Parliament in Brussels to explain the gaps in the social network in the data protection of its users, illustrated by the Cambridge Analytica scandal.

His late afternoon hearing by the leaders of the political groups of the assembly, originally scheduled in camera, will finally be broadcast live on the internet.

European Parliament President Antonio Tajani announced on Monday that Mr Zuckerberg had agreed to have his speech broadcast live on the web, following pressure from influential MEPs.Three days before the entry into force on Friday of European legislation to better protect the personal data of Europeans, some had urged Mr. Zuckerberg to be publicly accountable, as he had done at length last month to parliamentarians US.

The latter had subjected the young American billionaire to a shower of questions to understand how the firm Cambridge Analytica had been able to exploit the data of tens of millions of Facebook users without their knowledge, for use for political purposes.

The leader of liberal MEPs, Guy Verhofstadt (ALDE), threatened to boycott the meeting in Brussels if it remained private.

“There are more Facebook users in the EU than in the US, and Europeans deserve to know how their data is processed,” said Justice Commissioner Vera Jourova.

The announcement of a live broadcast was widely praised: “Transparency has won (…) A meeting behind closed doors would have been a joke,” said the leader of the Social Democratic MEPs, the German Udo Bullmann.

“The pressure has worked,” applauded the Greens.

According to figures provided by Facebook to the European Commission, data of “up to 2.7 million” Europeans could be transmitted “inappropriately” to the firm Cambridge Analytica, involved in Donald Trump’s presidential campaign.

Jourova repeatedly thanked Mark Zuckerberg ironically in recent weeks for proving by this scandal how strict rules were needed, despite the reluctance of the major players in the Internet, major consumers of personal data.

In front of the American parliamentarians, Facebook’s boss apologized, acknowledging that he had not “taken a sufficiently broad measure of our responsibilities” both in the protection of data and in the propagation of “fake news” (false news), in foreign interference in elections or hate speech on the internet.

To the delight of the European authorities, he even described as “positive steps” the new stringent rules that come into effect on 25 May in the EU.

The “General Data Protection Regulation” (GDPR) will create or strengthen individual rights and impose strict obligations on companies that collect or process personal information from Europeans, wherever they are established.

All companies and organizations collecting data, whether they are present on the internet or not, will have to comply with them, or face heavy fines, as well as major platforms such as Facebook, Google or Twitter.

These rules include for citizens a “right to know” who deals with their data and for what purpose, as well as a right to oppose their treatment, for commercial prospecting in particular.

They detail the conditions to obtain their suppression (“right to forget”) and provide that individuals must be warned in case of unauthorized access to their data, as in the case of the massive piracy suffered by the company Uber in 2016 , long kept secret.

On Tuesday, Mr Zuckerberg will first have a bilateral meeting in Brussels with Mr Tajani for half an hour in the late afternoon (at 16:00 GMT), followed by a hearing of a little more an hour broadcast live with the leaders of the political groups of the European Parliament, then a press conference of Mr. Tajani.

The day after his visit to Brussels, Mr. Zuckerberg must be part of the fifty leaders of major digital companies received in Paris by French President Emmanuel Macron.