Oui, there will be tricolor bunting. Balloons? Certainement. And when “La Marseillaise” is played, diners will be asked to stand. But here is the surprise about Monday evening’s celebration of Bastille Day at Chez Napoléon, the diminutive, cozy, venerable Manhattan bastion of La Belle France at 365 West 50th Street: The bistro will be open.

“Normally, we are closed Mondays in the summer,” said Marguerite Bruno, 87, whom everyone calls “Chef Grand-mère.” 

Already, across the city, there have been grand Francophilic celebrations of vin and fromage, cutthroat pétanque competitions and even a Web site, bastilledaynyc.com, that coordinated all the hoopla for an annual street fête on Sunday on East 60th Street from Fifth to Lexington Avenues. 

But here, “there are no parades; it is not the same as in France,” Ms. Bruno said, brown eyes bright with remembrance. “Ah, the public balls. Right in the streets.” 

For at least a decade after her grandson nailed it to the wall, a small sign near the kitchen of the family-owned restaurant between Eighth and Ninth Avenues proclaimed: “If Mama Ain’t Happy, Ain’t Nobody Happy.” (The sign is now in storage, thanks to wallpapering in progress.) 

The mama in question is, of course, the matriarch of this 44-seat, white-tablecloth universe of chunky pâté, blood sausage and frog legs laced with garlic. 

“Everywhere there is nouvelle, but here there is French tradition,” said René Morel, 76, a violin restorer from Manhattan and a Chez Napoléon loyalist who said he was “too old to remember” when he began coming there. 

He was discussing the 1715 Stradivarius played by his luncheon companion, the globe-trotting violinist Rony Rogoff, 62, who was attacking the artichoke vinaigrette appetizer on a recent afternoon. “When I’m here,” Mr. Rogoff said, “I think I’m eating at Grandma’s.” 

And he is. Even though she commutes to the restaurant from Bellerose, Queens, “This is my home,” Ms. Bruno said. 

It would be difficult to make the case that this unassuming, doughty, 48-year-old trouper is the very soul of France on American soil, but the restaurant is certainly an increasingly rare remnant, a survivor from the lost legion of French bistros on the West Side of Midtown.

“This is French territory,” Ms. Bruno said. 

It has outlived the departure of the old Madison Square Garden, the disrupting construction of Worldwide Plaza up the street, the post-9/11 economic slump and anti-French sentiment, Broadway strikes and the transformation of Hell’s Kitchen to Hell’s Breakfast Nook and its rising rents. 

And because of French restaurant attrition, Chez Napoléon is now the northern bookend in the Theater District to that other, southerly, Chez: the indefatigable Chez Josephine, a French outpost at 414 West 42nd Street. 

But compared with the latter’s oft-venturesome cuisine, Chez Napoléon is so old-school that “sometimes I ask tourists from France why they would want to come here, when they could go anywhere,” said Ms. Bruno’s 36-year-old grandson, William Welles, who holds forth behind the postage stamp of a bar. “They say it is getting hard to find this traditional, home-style fare in France.”

Grand-mère has always done the cooking, but these days, though she still stirs the sauce, she has yielded much of the heavy lifting to her sous-chef, Carlos Cisneros, 45, who has worked with her for 15 years.

This is a kitchen overseen by a grandmother who was taught in turn by her grandmother Julienne Meignen, “and also my aunt, Marie Ribon,” she said. 

And in 1943, in the German-French border town Saarbrücken, it was Ms. Bruno and her aunt who gave some bread and other morsels to an underfed French prisoner, Alfred Bruno, who was toiling in a Nazi work camp. A year later, Ms. Bruno surreptitiously opened the barbed wire at the camp, she said, to permit his escape to Metz. 

They were married in 1945, but no film for the camera was to be had, so their wedding picture could not be taken until later that year. It now hangs on the restaurant wall, and Marguerite’s welcoming face is just the same as it is now, save for a timeworn resemblance to the actresses Simone Signoret and Isabelle Huppert. 

For nine years, Marguerite and Alfred operated L’Hôtel du Puy, a hotel-restaurant in Auron, a ski town in the foothills of the Alps. But since the Brunos were unable to buy the property, and the French economy was crashing, “we decided to come to America,” said Ms. Bruno, who spoke in English and French, with translation by her grandson and her daughter, Elyane, 61, who runs Chez Napoléon and usually answers the phone. 

The Brunos arrived in New York in 1975 and opened a restaurant, L’Esterel, at 58th Street and First Avenue; it closed, and Ms. Bruno cooked in several places before buying the tiny, tidy, busy kitchen at Chez Napoléon in 1982.

“It is so hard to keep our prices reasonable, as the cost of meat and fish go up and up,” Ms. Bruno said. The restaurant, like so many other old-timers, is trying to negotiate a new lease for next year. “Rents are a problem for all of us,” she said. 

On the walls are reproduction French flintlocks, a battered trumpet, a map of Paris in 1578 and Napoleonic murals, some painted by Mr. Bruno, who died in 1992. There are also framed jigsaw puzzles (the restaurant sells a “menu” of puzzles with designs ranging from paintings by Monet to the ocean liner Normandie, from $17 to $22).

And in one of the two mini dining rooms is a framed facsimile of the Little Corporal’s renowned 1821 letter to the French before his death. “People ask if it is real,” Ms. Bruno said. “If it were real, would we have it on the wall?” 

Her daughter shook her head. “Napoléon,” she said, “his handwriting was very bad.” 

Ms. Bruno padded from the kitchen to the bar and sat before her grandson at the lone seat. “I only started drinking Scotch when I came to America,” she said of her custom of sipping “just one glass of Dewar’s” after the dinner rush. 
“But we are allowed,” her grandson said fondly, “to fill that glass again.”