Facebook has been given a deadline to provide more information about what is done with users' data, or it will face sanctions from the European Commission.
She said her "patience" had run out and threatened to apply penalties.
Facebook, which has to act by 31 December, said it had made some changes and would continue to co-operate.
"If we don't see progress, the sanctions will come," Ms Jourova told a news conference. "This is quite clear. We cannot negotiate for ever, we need to see the results."
BBC News.
