When famed chef Daniel Boulud hosted a soirée last month celebrating his 20 years in Palm Beach, well-heeled guests nibbled on caviar in the garden of the Brazilian Court hotel, where his Cafe Boulud is situated.

But there was a clear divide between the tony island’s old guard — women dressed in florals and pearls — and the Northern newcomers in monochrome sheaths and cashmere wraps.

“They are bringing life and energy to Palm Beach,” Yana Schlesinger, whose husband, Richard, and his sons own the chic hotel, said of the new influx of residents from New York City.

But not all veteran residents are joyful about the transformation.

“One man’s vibrant is another man’s noisy and unruly,” Shannon Donnelly, a legendary society columnist for the Palm Beach Daily News, told The Post. “People here go about their business quietly, go out and go home early. Now there is so much rudeness. There are contretemps over parking spaces and waitresses are crying.”

As more financial companies set up shop in West Palm Beach, high-earning executives and their families have joined the wave of people moving south for the weather, lifestyle and tax benefits.

For better or worse, northerners have infiltrated one of the world’s most insular enclaves, snapping up some of its priciest homes, filling its schools and restaurants, and changing its tenor.

“I can’t get on a tennis court here anymore,” Schlesinger said with a sigh.

And household staff is in such short supply that brazen newcomers are making tempting offers to employees already engaged — even approaching people strolling in baby carriages on the street. “Nanny poaching is alive and well,” said Donnelly.

Suddenly, school admission is a challenge.

“Friends can’t even get their kids into a [private] school,” said Francie Leidy, a sales associate at Brown Harris who comes from a long line of Palm Beach stock. “But we can all say thank you for the bump up to our real estate values!”

Donnelly notes that the new guard has persuasive ways of edging its way into the best schools. “The guy who bought the most expensive place in Palm Beach comes down with his kids. There is no room in the schools but he comes up with a gigantic donation. Suddenly they have room.”

Palm Beach’s famously exclusive social clubs — like the Everglades, the Bath, and the Tennis Club — however, are not as easy to infiltrate.

“Membership at the Beach Club has gone up five times since I joined,” said Todd Herbst, co-owner of Big Time Restaurant Group, which has 18 restaurants in Florida.

One society doyenne predicted that the trophy wives of hedge funders will want to vacate the area once they realize that the clubs will not allow them entry — at any price.

But others say that old Palm Beach chic isn’t a draw if you haven’t lived there forever, especially because the newcomers have imported their own culture.

New York restaurants like La Goulue, Le Bilboquet, Felice and Le Colonial have all opened Palm Beach outposts, complete with maitre d’s known to their migrated clientele.

“I don’t think clubs are the priority for the new financial set because they tend to travel more for pleasure,” said Doug Evans, President and CEO of the Palm Beach Chamber of Commerce. “[A new resident] I was with yesterday just came back from taking his kids toAntarctica. It used to be that the social thing here was the galas and parties, but now all the packed restaurants are just as exciting and you can’t get into them unless you book six months in advance or know someone.’’

But the traffic that comes with that has become a major frustration for longtime inhabitants.

“Yesterday it took me 30 minutes just to cross the bridge — and what’s with all the horn honking?” Leidy asked of New Yorkers who drive like they’re still in the city.

Style, meanwhile, is one of the most obvious divides.

Classic Palm Beach women stroll on Worth Avenue in the tropical, ladylike colors of Lilly Pulitzer and try not to wince as they pass shoppers in the all-black New York uniform.

“It’s the worst you can imagine — we see jeans with holes in them,’’ said Nancy Traylor, who has long had a home on the island.

Donnelly said she can spot northerners at a glance: “These hedge fund guys were at the post office during the day wearing Gucci belts. One was driving a Maybach and the other a Bentley. I didn’t even have to look to know the license plates were from New York. Men [who are old-money Palm Beach] tend to dress like they just got off the golf course. Big cars and good jewelry should stay home during the day.”

Paul Labrecque, who owns salons on Palm Beach island and in New York, has seen a seismic shift in the tiara set. “There is a huge change,” he told The Post. “Before COVID, people here still wanted bouffants and a little flip. Now everyone wants Manhattan-style straight [hair] or soft waves. Even the more mature women are wearing trendier clothing.”

“It’s a new era,” said financial adviser Brian Hogan. “You think you will see Jon Bon Jovi” — a new arrival who bought a $43 million home on the island — in a yellow shirt, pink pants and loafers? The guys who can afford houses here now want the beauty, safety and sophistication, but don’t need to buy into the old establishment.”

And there are some newcomers who respect the old approach. “At the Everglades club there is a lady at the door checking what you wear,’’ said Susan Saunders, who recently re-located to Palm Beach with her husband. “We find the un-woke eccentric and charming.”