May 12, 1997 12:00 PM

BY ALL APPEARANCES THE HAPPY couple had no fear of showing their affection in public. At a March 9 horse show near her-home in the South of France, Princess Caroline spent the afternoon watching daughter Charlotte, 10, in competition. At her side was Prince Ernst August of Hanover, who has become a familiar figure in St.-Rémy-de-Provence, the town where the princess has a chic farmhouse. After a picnic the attentive Ernst, 43, and Caroline, 40, strolled about the grounds. When they kissed, a vigilant cameraman caught the moment.

So, it seems, did Ernst’s wife of 16 years, Chantal Hochuli. On March 13 Paris Match ran a shot of the embrace; days later, the French weekly Voici ran a photo of Chantal scanning an article about the twice-married princess in an Italian weekly. But Chantal, it seems, had already made her move: By early March the attractive blonde (the daughter of a very wealthy Swiss architect) had filed for divorce in London, where the Hanovers live with sons Ernst, 13, and Christian, 11.

By one account, Chantal, 43, simply lost her tolerance for tabloid reports about her troubled marriage. “A woman can only take so much humiliation,” notes the columnist Taki Theodoracopulos, a family friend. “Chantal is a saint…[and] we’re all very sad.”

That sentiment seems to hold true in royal circles, where Ernst—a descendant of Britain’s King George I—is respected as the head of Germany’s once-powerful House of Hanover. The prince’s lack of discretion, it seems, has piqued his royal relations, who fear that his $160 million fortune may be pared by a divorce. According to a friend who spoke to Match, he “allowed himself a few discreet infidelities” in years past, “but he always tried to behave like a gentleman.”

Ernst’s dalliance with Caroline, however, has been bolder. Friends for years, the prince (whom Princess Grace, Caroline’s mother, had once championed as a husband for her older daughter) and Caroline made a jaunt to Bangkok in January 1996 and were promptly spotted by the press. Last summer the two were seen dining a deux in London. In the fall, when Caroline was coping with a scalp disease that had left her bald, Ernst was often at her side. When she flew to Manhattan for a benefit in November, it was the prince who reportedly stayed with her children Charlotte, Andrea, 12, and Pierre, 9.

The question, of course, is whether a divorce for Chantal will mean a marriage for Caroline. “I think [so],” says a friend of the Hanovers’. “Ernst needs somebody who can take care of him.” In the meantime, the romance continues. On April 17 the pair ended a weeklong idyll in the ski resort of Blue River in British Columbia. Reporting that the princess had to “jump on a plane to Vancouver, put up with a nine-hour time difference and drive [365 miles] once she arrived,” the magazine Voici noted dreamily, “it’s a sign that she’s really in love.”


NINA A. BIDDLE in London and CATHY NOLAN in Paris