The allure is Riviera-style dining: a soaring dining room done in soothing greens and blues; a bar that looks ripped from Graydon Carter-era Vanity Fair; refined fish; and delicate pastas served family-style. Ingredients are portioned with restraint; dishes are gleaming white; courses are painstakingly timed — “served à la minute,” our solicitous server informs us, as though revealing a state secret. The meal unfolds like a civilized dinner party, not a Sunday night free-for-all with five people reaching for meatballs.

Ascending the imposing staircase from the Four Seasons lobby toward LPM, I felt out of place in corduroys and a fall jacket. Men in sharply tailored suits; women in gravity-defying heels: Sophistication oozed from the foyer up toward the second floor, where I followed a thump-thump beat toward what I assumed must be LPM.

But no. I had stumbled into the moody Zuma, the hotel’s Japanese restaurant. A hostess eyed me uncertainly as I waded into the darkness.

Chocolate mousse at LPM.Jonathan Wiggs/Globe Staff

“You must be looking for LPM,” she said. What gave it away?

A few steps later, I was greeted at LPM like royalty. Not one but two hostesses seemed genuinely delighted to be there — and sincerely apologetic when informing the besuited man without a reservation that the next table would become available at 9 p.m. Try Zuma, they said.

The circular dining room is capacious and cheerful; men in suits swooped in constantly to check on the table: offering multi-grain bread; pouring more water; explaining why there are lemons and tomatoes at each table that belong to a still-life painting.

“Many people think they’re fake, but they’re really used to make a salad,” our server said conspiratorially. This is a DIY enterprise: slice into a lemon and a tomato, drizzle it with olive oil, and slather it atop bread that seems to arrive every three minutes.

“It’s a tradition in the South of France. When you visit someone’s home, it’s common to have fruit on the table, and a knife. Essentially, you’re telling guests: ‘This is your home. You should feel more than welcome,’” manager Roberto Mena shared before opening. “It’s just something really grounding. It’s a beautiful thing, really.”

Beef tartare at LPM.Jonathan Wiggs/Globe Staff

This didn’t seem like a crowd who’d want tomato splatters on their silk shirts, but I spied a few people slicing away. (We did not.) I wouldn’t describe LPM as “grounding” whatsoever, though, and that’s a good thing. It is transportive, from the soaring ceilings to the backlit bar. For a moment, I pretended to star in “Bright Lights, Big City,” and that it was 1980-something in Manhattan. It’s that kind of place.

Transportive does not mean snobby, however, and I have to give LPM credit: Despite the posh surroundings, service is more comfy bistro than ladies-who-lunch fussiness. Our server admitted that he didn’t know where our oysters came from, but checked and then returned to report that they were from Damariscotta, Maine, reading details from a notepad. When my dining companion complimented my haircut, he overheard and chimed in with his own kind words — and this didn’t feel slimy at all. We felt genuinely tended to.

A table setting at LPM.Jonathan Wiggs/Globe Staff

What to eat: This is a luxe French Mediterranean menu spanning escargots, homemade pastas, and grilled seafood. Consistent ingredients appear throughout: green chili, lemon, and tomatoes. LPM clearly knows what it does well.

To start, we tried sliced octopus with lemon and green chili dressing. The octopus was cut radish-thin, enough to be translucent. It was like eating soft glass. The green chili dressing was bright and light, a true delight. Damariscotta oysters came with a homemade tabasco sauce: smoky, vinegary, and with a lasting zing unlike any tabasco I’d tried before. Again, the preparation was simple. No assortment of cocktail sauces or mignonettes. No decision fatigue.

Oysters with homemade tabasco.Jonathan Wiggs/Globe Staff

We hemmed and hawed about one more dish. Maybe something with potatoes? Our server thoughtfully calibrated the pros and cons of frites versus a crock of potato gratin, ultimately convincing us that the heftier gratin would offset the thin octopus. He was correct.

I am not sure I’ve eaten a more sublime potato formation: craggy and crispy on top, with ringlet-thin potatoes swimming in a caftan of nutmeg cream. I was ready to book a room and curl up with it for a nap.

We were warned that our entrees might emerge before our starters, since dishes arrive as they’re ready, but this wasn’t the case here. Our entrees came out in tandem: For my dining companion, a dramatic quartet of butterflied, head-on prawns with a smoky golden-green chili coriander sauce that had us licking the shells. (Probably not proper Four Seasons behavior.)

I ordered Chilean sea bass with chili and lemon confit. On the plate, it looked wan, something you’d receive at Kripalu after a meditation session. But first impressions can be deceiving: This was a seductively supple piece of fish. The confit’s blend of tartness and spice added texture and surprise. Maybe I’ll take up health food.

Salted baked bass at LPM.Jonathan Wiggs/Globe Staff

Or not. For dessert, we split a truly outrageous warm chocolate mousse that quivered like Mount Vesuvius when nudged by a fork. It was like eating silky cake batter. The restaurant is also known for French toast with spiced ice cream. Next time, maybe, without a potato gratin prelude.

What to drink: LPM specializes in a tomatini, which looks like gazpacho in a glass and smells soothingly of olive oil. It’s a complex, savory drink, complete with a tomato garnish, presented by a server wielding a gigantic pepper grinder. There are also herbaceous gin and tonics, toasted pineapple martinis, and a rosemary-and-hibiscus Paloma. A Limonade Noire, their signature mocktail, combines verjuice with rosemary-infused honey and activated charcoal. The bar is busy, and every so often, we heard cocktail shakers clatter across the dining room.

A tomatini at LPM.Jonathan Wiggs/Globe Staff

The takeaway: One of the most gratifying meals I’ve enjoyed in Boston for quite some time. Service is polished. The menu is confident. Dishes are simple and well-executed. Desserts are stunning. The people-watching? That’s delicious, too. Boston needs more places that make diners feel as if they’ve arrived. This is one of them.

LPM, 1 Dalton St., Boston. 857-576-2700, www.lpmrestaurants.com. Cocktails $18 and up; hors d’oeuvres $9 and up; entrees $29 and up.

Kara Baskin can be reached at kara.baskin@globe.com. Follow her @kcbaskin.

Dining and Cooking