"No one in Correns knew a thing," says an official from the French village, where the couple tied the knot at their wine-growing estate, Château Miraval.
"It was a marriage which seems to have been carried out in total intimacy and absolute discretion," the official tells PEOPLE.
The wedding license was obtained in the couple's home state of California.
Château Miraval had long been rumored as a preferred wedding site for the pair, who first settled there in 2008 just before the birth of their twins, Knox and Vivienne.
The sprawling property has a 35-room main house, an ancient chapel and a working vineyard spread over 1,100 acres.
Over the years, design enthusiast Pitt, 50, has taken the lead in renovating the house to suit his architectural and aesthetic interests, picking up fabric, wallpaper and furniture in Paris and at various art fairs.
Most recently, during a 10-day visit in July, the actor quietly saw to certain details, including making contact with a small local florist shop several villages away, PEOPLE has learned.
Adding to the surprise factor, the couple fit their big day into a small window in a schedule full of work commitments. Jolie, 39, has been prepping for the couple's upcoming drama, By the Sea, in Malta – she's costarring with Pitt, writing and directing – and Pitt spent his fifth day as a newlywed promoting his upcoming WWII drama, Fury, in England.
Largely keeping his new ring out of view during the photo call – at one point he even slipped it into his jacket pocket – Pitt "wore his band but didn't play with it like sometimes people do when they have a new ring," says one reporter who attended the press event, which was held at the Bovington Tank Museum in Dorset, about two-and-a-half hours from London. The couple exchanged rings designed by Robert Procop.
"At the end, we were just talking and I said, 'Congratulations!' and he gave me a big smile and said, 'Thank you, man!' " adds the attendee, noting that Pitt had a newlywed glow. "He looked amazing today. He was very animated, very invested. Very alive."
Adds another attendee: "He was very nice, very open and in a very good mood."
Reporting by MARY GREEN, PETER MIKELBANK and MONIQUE JESSEN