The 39-year-old actress and director said as much in the latest issue of Italian magazine Io Donna, according to Us Weekly.
"Before the wedding in France with the kids, Brad and I were already married in California," said Jolie. "As Americans, we couldn't marry legally in France."
Per the actress' recount, the couple's first wedding was a casual affair.
"One day I said to Brad, 'Let's meet up at 4:30 p.m.?'" she revealed. "I called a justice of the peace and we signed the documents."
The actress' rep confirmed to Us Weekly that the couple's children all had roles in the event, for which Maddox, 13, and Pax, 11, walked Jolie down the aisle, Shiloh, 8, and Knox, 6, served as ring bearers and Zahara, 10, and Vivienne, 6, "threw petals from the garden."
Jolie and Pitt have been together since 2005.