Hikers have long demanded a right of way through a pristine stretch of coast near Saint-Briac-sur-Mer on Brittany's Emerald Coast, but villa owners have filed lawsuits to block access to the pathway.
Even though legal appeals continue, local authorities have continued to build the trail, which now traverses the Essarts estate that has been in Kerry's family for decades.
“The pathway is open, it's beautiful and the landscape is amazing,” Patrice Petitjean, president of a local hiking association, told AFP.
“People were getting impatient, they were pulling down the barriers to get in,” he said.
David Harel, director of the regional authority in charge of ocean and coastline management, acknowledged that hikers had already started accessing the pathway despite legal challenges.
French law dictates the country's coastlines must be accessible to all, similar to Britain's “right to roam” regulations.
But Saint-Briac property owners have steadfastly refused to allow access and filed a series of legal moves.
They included Brice Lalonde, a former French environment minister and ex-mayor of Saint-Briac — and also Kerry's first cousin.
Their grandfather James Forbes bought the Essarts castle in Saint-Briac in 1928 and it has remained in the family since, being rebuilt as a villa after it was confiscated and later destroyed by the Nazis in World War II.
Kerry, who speaks French, has regularly spent time at the estate.
Lalonde has argued that even though he supported the coastal path, he was worried the access to his property could pose a security risk to Kerry, a former US presidential candidate who was later secretary of state under Barack Obama.
“This is major progress, but I won't count the chickens before they hatch. If the appeals court cancels the decree allowing access, we'll be in a difficult position,” Petitjean said.