Félix Lebrun has the crowd eating out of the palm of his hand. He raises his arms. They cheer. He pumps his fists. They roar. He struts around the sold-out arena, prowling the floor, basking in the noise and the adulation.

In that moment, that first flush of victory, Lebrun is not a bespectacled 17-year-old table tennis player from Montpellier. For everyone present — up to and including the French former soccer hero Zinedine Zidane — he is a rock star.

This sort of thing has been happening a lot in Paris over the last week. At the fencing competition, held in the lavish surrounds of the Grand Palais, fans waving tricolors have produced enough noise to echo down the Champs-Élysées. The Stade de France shook when France’s men won gold in rugby sevens.

Each of Léon Marchand’s triumphs at the swimming pool has been greeted by unrestrained delirium, not just inside the arena at La Défense but across the city. The sound from the stadium at Invalides, home to archery, has been loud enough to wake Napoleon.

The test, for these Olympics, was always going to be whether Paris — a place that prizes chic and wears its aloofness as an impeccably accessorized badge of honor — would give itself over to the carnival spirit of the Games.

The answer, it turns out, is yes. Paris has, for the last week, completely lost its cool.

This may well have come as a surprise to the Parisians themselves. The weeks and months preceding the Games were buffeted by a steady torrent of complaints and anxieties and apparently inevitable catastrophes rearing up on the horizon.