It has been a long erosion. He handed over a novel from his mother’s library, “La Fille de l’Air,” by Pierre Lamballe, the pen name for one of de Gaulle’s top aides, Pierre Lefranc, who died in January. Mr. Lefranc demonstrated against the German occupation on the Champs-Élysées in 1940, was wounded by a grenade and was arrested. He fought in the Resistance, worked for de Gaulle, and in May 1968, when the student uprising nearly overthrew the government, he helped organize a sprawling pro-de Gaulle demonstration, again on the Champs-Élysées.

The novel, published in 1983, is a light one, about a Frenchman taking advantage of a Parisian August to try to embellish his life and pick up women. But even the shape of the croissants at his favorite cafe on the Champs-Élysées had changed. “Things are no longer what they were,” he thinks.

Jean-Noël Reinhardt, the chairman of the Comité Champs-Élysées, a merchants’ association, says that, of course, the avenue has changed, as the world has.

“The Champs-Élysées is many different things at the same time,” said Mr. Reinhardt, who used to run Virgin stores here (also on the Champs-Élysées, but given the costly rents and the state of the music business, probably not for long).

“It represents France symbolically in the world,” he said, with the Arc de Triomphe, the annual Bastille Day military parade and the finish of the Tour de France. “For the French, it’s the shop window of global commerce, a bit like Fifth Avenue in New York.”

More like Times Square, actually. About 300,000 people daily, and 500,000 on weekend days, walk the wide sidewalks along the avenue’s 1.2 miles. Nearly 200,000 Parisians work largely white-collar jobs in the area. They need to shop and eat, and many now seek fast food rather than leisurely lunches, which helps explain the four big burger restaurants (two McDonald’s and two Quicks), the sandwich shops and the chain outlets like Pizza Pino, Léon de Bruxelles and Chez Clément.