And while steak tartare shows up on practically every brasserie menu, chefs now recognize that a hamburger is not simply six ounces of chopped lean beef grilled until crusty.

“No, that would be an error,” said Ms. Grasser-Hermé.

“A hamburger is the architecture of taste par excellence,” she explained. “The meat needs to be a mix of fatty and lean. Not raw, not rare. It must be medium rare. At the same time the bread needs to be smooth, tepid, toasted on the sesame side. I like to brush the soft side with butter. There needs to be a crispy chiffonade of iceberg lettuce. Everything plays a role.”

In developing the Salle Pleyel burger, Ms. Samuel and Ms. Ezgulian felt the weight of tradition. “We’re a little terrified of making a mistake,” said Ms. Samuel. “We cling to things like the soft buns, sweet-and-sour pickles, onions, tomatoes, cheese. We need these guideposts because we don’t have the history, the context. Otherwise, for us, it’s not a burger. It’s a hot sandwich.”

Yet Ms. Ezgulian has taken some liberties. The current version of her burger is a riff on steak tartare. She’s kneaded a mixture of chopped sun-dried tomatoes and tangy cornichons and capers into the ground meat. Parmesan shavings stand in for the usual Cheddar.

Céline Parrenin, a co-owner of Coco & Co, a two-level place devoted to eggs that opened in St.-Germain last year, didn’t feel any such compunction when she and her business partner, Franklin Reinhard, invented the Cocotte Burger. The Cheddar cheeseburger, with pine nuts and thyme mixed into the meat, sits on a toasted whole-wheat English muffin pedestal. In a wink at the restaurant’s egg theme and recalling the time-honored steak à cheval, a fried egg is placed on top.

All the chefs are making hamburgers for the first time, and they are uncertain about the exact cuts of beef they are using. Mr. Alléno, for example, simply relies on his butcher, Yves-Marie Le Bourdonnec, whose shop, Le Couteau d’Argent, is in the Paris suburb Asnières.

For Mr. Alléno’s burgers, Mr. Le Bourdonnec delivers a mix of chuck and beef rib. But the butcher thinks the American T-bone steak is an ideal cut. The T-bone does not exist in France, but to make his point, Mr. Le Bourdonnec made his own. He combined a piece of filet, which is tender but less flavorful, with a piece of contrefilet, which is marbled and tasty, but slightly less tender.