My favorite fragrance used to be Le Ritz Paris. It was a deep amber that hit you the minute you spun through the hotel’s revolving door. It felt warm and rich and, to my wholly American sensibilities, like the distillation of French luxury.

I’m not entirely sure if I really loved the fragrance or the place itself and its almost comical opulence: satin duvets and gold swan faucets, cocktails garnished with roses, sweet butter stamped with swirly R’s, gym equipment wrapped in peach terry cloth, and music piped underwater in the pool.

When I asked the general manager many years ago about the fragrance, he held up a finger. “One minute,” he said, disappearing into a back room and returning with a plastic bag holding a slab of white wax. This wasn’t the romance I’d imagined. According to my high-school French, the Ritz housekeepers would slip the fragrance-soaked wax behind the radiators, where the heat would flood the amber scent through the rooms. Kind of like a Glade PlugIn, only Parisian and waxy. I packed the slab and tried it in my New York apartment, where, devoid of tapestries and peach terry cloth, it just didn’t translate.

More and more hotels are greeting their guests with a blast of signature scent upon arrival, whether they like it or not. “What are you doing all day? Well, you’re breathing,” says Matt Butler, a hotel buff who obsesses about these things. Might as well brand and market the air you breathe.

With the renovation of the Ritz came an updated scent that’s still amber-based. “This scent is a subtle and refined invitation to enter and be immersed in the unique world and heritage,” says Arnaud Leblin, director of heritage for the Ritz Paris. Every day, the staff sprays this Ambre Péristyle perfume in the hotel’s public and private rooms. “It is important that our guests are immersed in the same olfactory universe wherever they are in the Ritz Paris.”

Kind of like a Glade PlugIn, only Parisian and waxy.

Some people want the immersion to travel well beyond the Place Vendôme and become so total that they’re practically dripping with the stuff. Butler, the founder and C.E.O. of the Butler Method International, a college-counseling service, is one such Ritz-fragrance devotee. He bought multiple bottles of the scent at the hotel’s gift shop and tried to pour the liquid into a diffuser at home. No luck.

He discovered the source of the fragrance, Emosens, in Lyon, and begged them for an oil that he could diffuse into the air of his apartment. As delightful as they were, they would under no circumstances share the proprietary Ritz blend with him or anyone else. “It’s the most frustrating thing,” Butler says, despondently. “Everything else I’ve tried is ersatz and sugary.”

The Aman Resorts have fragrances; so do the One&Only, the Park Hyatt, the 1 Hotel, the Auberge Resorts, and the Baccarat. The Carlyle, a Rosewood Hotel, recently commissioned David Moltz, the founder of the fragrance line D.S. & Durga, to create a perfume in its name, riffing on the hotel’s classic yellow soap. The Maker Hotel, in Hudson, New York, offers a fragrance library and a perfume mini-bar in each room.

Many of these fragrances don’t make it past checkout time and onto human pulse points. An exception is Eau d’Italie, the scent that originated at Le Sirenuse hotel, in Positano, in 2004. Marina Sersale, a member of the hotel family, worked with Bertrand Duchaufour, a seasoned perfumer, to try to bottle the spirit of the place. “One of my strongest memories of summers in Positano is racing my brother and sister across the terra-cotta tiles, which were scorching hot,” says Sersale.

That memory kicked the fragrance in motion starting with a warm mineral note. Duchaufour added incense, patchouli, and musk, inspired by the church down the hill, and sweet yellow clover, magnolia, a bit of tuberose, bergamot, and black-currant buds to capture the fresh Mediterranean air.

Sersale planned to spray the scent in the hotel lobby, offer it in soap, bath gel, and body-lotion forms in the rooms, and sell it in the hotel’s Emporium. “We were really babes in the woods,” Sersale says. When magazines caught wind of it, the scent blew up. “It started in a very innocent and unplanned way.... We had visions of the fragrance traveling far from the hotel. I think it enriches the experience of staying [here]. It’s something intangible that you are happy to take with you.”

When Lev Glazman and Alina Roytberg opened the Maker Hotel, fragrance was top of mind, which sounds bizarre until you learn that the two created Fresh, the natural-scent-and-skin-care brand now owned by LVMH. They wanted the hotel to be an incubator, “the start of a lifestyle-and-fragrance brand,” as Glazman describes it. Almost everything in the hotel is available for purchase, but the perfumes and scented candles are the big draw.

The hotel library is filled with both books and more than 100 scents for guests to spritz at will. Glazman and Roytberg hired a mixologist to serve cocktails inspired by the scents. “We want to create an immersive brand experience,” he says. Their dream was to “create fragrances that connect you to the place itself,” Glazman says. Now the scents live on their own, at Goop, Bluemercury, and the Maker boutique, in Chelsea.

That notion of containing an experience in a scent may have explained why my childhood home in St. Louis was stocked with Carlyle soaps. My father would always return from his business trips to New York with a few bars stuffed in his briefcase. It didn’t matter that his annual reports were laced with its honeysuckle scent. Each yellow bar in each soap dish felt like a shard of urbanity in the bland, humid suburbs. My family, transplanted New Yorkers, treated the soap and the Sunday New York Times as life rafts.

This year, the Carlyle executives asked Moltz to translate that yellow soap into “wet amenities,” which sounds slightly disgusting but just means shampoo, conditioner, shower gel, and body lotion. “The Carlyle is the pinnacle of the fancy New York hotel,” Moltz tells me. “And the perfume is a Who’s Who of fancy fragrance ingredients.” So who exactly is who? Citrus notes (lime, neroli, bergamot), linden, honeysuckle, and sandalwood. It’s both unobtrusive and rich.

This surge of hotel fragrances doesn’t entirely surprise me, given my own weakness for the innumerable charms of a great hotel. Hotels are where I live my best life, where I bring only the clothes I love and hang them in roomy closets. There is no junk mail and no clutter. The towels are always fluffy, the sheets are always crisp, and the air is always filled with amber or honeysuckle or a mineral-citrus-incense scent, spritzed methodically, invisibly, as if by magic.

Linda Wells is the Editor at Air Mail Look