The CDU chief's comment came after her party and its centre-left coalition partner SPD suffered their worst scores in Sunday's European election -- a result partly blamed on the fact that some 70 YouTube stars had urged Germans not to vote for either party.

Addressing the issue on Monday night, Kramp-Karrenbauer said if 70 newspaper editors had called to boycott parties ahead of an election, that would be classed "clearly as propaganda".

"The question is... what are rules from the analogue realm and which rules should apply to the digital realm?

"I'll tackle this discussion quite aggressively," said Kramp-Karrenbauer, or AKK as she is dubbed in Germany.

Her comments immediately sparked a storm on social media with #AKKRuecktritt (AKKresign), #annegate, #Zensur (censorship) and #Meinungsfreiheit (freedom of opinion) making up the top four topics trending on Twitter in Germany.

Many users pointed to article five in the German constitution guaranteeing freedom of opinion, speech and writing.