In March of this year, the European Commission created guidelines and recommendations for the removal of “illegal content” (primarily terrorist propaganda) from websites within Europe. At the time, the rules were voluntary; now the EC is going to impose fines if publishers and tech companies fail to comply.

Yesterday, the Financial Times reported that regulations will be published next month for review. The mandatory rules would require the content in question to be removed within one hour following notification.
https://marketingland.com/europe-to-punish-sites-for-not-removing-illegal-content-within-one-hour-246371

Also see:

EU considers fining tech companies for extremist content
The European Union is weighing strengthening its rules against extremist content on technology platforms and could fine some of the world's largest social media firms.

Some members of its European Commission want to fine Facebook, YouTube and Twitter and other companies for failing to remove terrorist propaganda and other types of extremist content from its platform, according to the Financial Times.
http://thehill.com/policy/technology/402649-european-union-considering-fining-tech-companies-for-extremist-content

Brussels to act against tech groups on terror content [registration]
Threat of fines after commission sees insufficient progress on voluntary action
https://www.ft.com/content/a4068e88-a22a-11e8-85da-eeb7a9ce36e4