An online privacy group is hoping to secure hundreds of millions of euro in compensation.
That's for Irish Facebook users affected by a recent data breach.
A group is taking a legal case against the social media company, after the leak.
That's including names, emails and phone numbers of over 500 million people in more than 100 countries.
It was published on a hacking forum earlier this month.
Also, with information for around 1.5 million Facebook users in Ireland.
Possibly Significant Compensation After Facebook Leak
Digital Rights Ireland now wants those caught up in the leak to join a legal case.
It's suing the company for damages - in what it says will be the largest ever mass action of its kind.
Antoin O'Lachnain from the group says the level of compensation could be significant if the case is successful:
"Going by cases that have occurred in the past, it could be anywhere between €100 per person, to the low thousands."
"So say, with close to a million complainants in Ireland, close to a million have been affected by this."
"That could potentially be hundreds of millions of euro."
DPC Investigating Facebook Leak
Meanwhile, the Data Protection Commission is already investigating this to see if Facebook broke GDPR rules .
Here's Spin's Tech Correspondent Jess Kelly:
"If they find there was a breach of GDPR, the max they can fine is 4% of global turnover or €20m."
Additionally, Facebook says it's continuing to strengthen its systems - and will cooperate fully with the DPC inquiry.
