The penalty was for “illegal actions committed in the 'Cambridge Analytica' case, the company that gained access to the data of 87 million users through an app for psychological tests,” it said in a statement.
The social media network has been dogged by controversy in the wake of revelations that defunct political consultancy Cambridge Analytica used private data from tens of millions of Facebook users for political targeting.
The same consultancy worked on both the Leave campaign in the UK's Brexit referendum of 2016 and on Donald Trump's election campaign in the same year.
The privacy watchdog said the fine related to the download of the Thisisyourdigitallife app by 57 Italians via the Facebook login, which saw data gathered on a further 214,077 Italian users without their consent.
The data in this case was not passed on to Cambridge Analytica, it said.
“We're are strongly committed to protecting privacy, and we have invested in resources, technology and partnerships, as well as hiring over 20,000 people to work on security in the last year alone,” Facebook said.
Critics slammed the watchdog for handing the social media giant a relatively small fine, while analysts said it was low because the offence was committed before Europe's new data protection framework came into force.
In December, Italy's competition authority fined Facebook 10 million euros for selling users' data without informing them and “aggressively” discouraging users from trying to limit how the company shares their data.