Gilbert Chagoury, a British billionaire and philanthropist who has given millions of dollars to the Clinton Global Initiative, was denied a visa last year to enter the United States because, according to the U.S. government, he was suspected of supporting terrorism.

Chagoury denies the allegation, saying the U.S. Department of State relied on bad intelligence and is in turn suing federal agencies that he claims leaked information about him to a reporter. His suit is thought to be the first case brought under the Judicial Redress Act, which President Barack Obama signed in February, and could test whether the privacy measure has much bite. The law gives citizens of the European Union the right to file lawsuits in U.S. courts against federal agencies for alleged Privacy Act violations.

Edward McAndrew, a privacy and cybersecurity lawyer at Ballard Spahr in Philadelphia who is not involved in the case, called Chagoury's complaint "a dandy of a first lawsuit."

"If the allegations of the complaint can be proven, it does appear that there would be a violation of the Privacy Act," McAndrew said. "That's a big 'if,' of course, because the main question under the Judicial Redress Act is whether there's been a willful or intentional disclosure of protected information by a government agency."

McAndrew said he'll be watching to see if the government pushes back against disclosing information to Chagoury. There are a series of exemptions the government can invoke to shield or restrict access to documents that relate to law enforcement investigations or national security. Whether Chagoury is able to get the documents and other evidence he wants will show if the Judicial Redress Act has "teeth," McAndrew said.