Jourova said Facebook's quick revelation of the case demonstrated that new European rules on data protection implemented earlier this year are working.
The EU's top data privacy enforcer expressed worry that Facebook had lost control of data security after a vast privacy breach that she said affected five million Europeans.
"It is a question for the management, if they have things under control," EU Justice and Consumer Affairs Commissioner Vera Jourova said in Luxembourg. "The magnitude of the company ... makes it very difficult to manage, but they have to do that because they are harvesting the data and they are making incredible money on using our privacy as the commodity," she added.
