The lawsuit said the documents relate to an IRS examination of the company's tax liability for 2010, when Facebook's tax return reported royalty income from transfers of intangible property to Facebook Ireland Holdings Unlimited.
"Facebook complies with all applicable rules and regulations in the countries where we operate," Anteneh Daniel, a spokesperson for the company, said in a statement with Reuters on Thursday.
Facebook transferred to the Irish company rights associated with its worldwide business, with the exception of the United States and Canada, the lawsuit said.
Facebook reduces its tax bill by having non-U.S. clients pay advertising fees directly to an Irish subsidiary called Facebook Ireland Ltd.
This subsidiary reported revenues of 4.8 billion euros in 2014, the last year for which accounts are available.
But Facebook Ireland Ltd reports low taxable profit, of just 13 million euros in 2014, because it pays a significant chunk of its revenue to another Irish-registered company called Facebook Ireland Holdings, in return for the use of the Facebook platform.