The signs that a protest is happening in Paris are nearly always the same: the quiet of blocked-off streets; the neat rows of police vans containing the gendarmerie stretching down the boulevard; the sound of drumbeats and whistles and the neon red flares that spit smoke into the sky. For six months last year, those signs were constant and ubiquitous, as furious, sometimes violent marches and general strikes protesting President Emmanuel Macron’s pension reforms brought Paris to a standstill. Students and activists, public-transit operators, custodial staff, medics, mechanics, teachers, oil-rig workers, writers and celebrities all gathered to rail against Macron’s plan to raise the national retirement age by two years, to 64.

As transit walkouts snarled traffic and sanitation strikes caused trash to pile up in the streets, the protests were ridiculed abroad. Why must the French, among the best-protected workers in the Western world, make such a racket over two years of work? But for the demonstrators, this missed the point: It is because French workers put up a fight that they are protected. “We actually have laws on our side,” Samira Alaoui, a union representative at Teleperformance, a digital business services company, told me. “We are a model for the world. If we don’t do anything, who will?”

In 2023, France seemed less the exception than the rule. There was a surge in labor activity around the world last year — strikes and victories — as much as or more than any year in decades. This was true in the United States, where the Writers Guild of America, the United Auto Workers and the UPS Teamsters all won significant concessions from executives. In Britain, nurses went on strike to protest staffing shortages and patient backlogs at the National Health Service. Still, it was perhaps in France that labor’s rise was most visible — most combustive and most telling. France has always been a vanguard of leftist politics. Today it is one of the few Western democracies where a far left has managed to survive and even thrive, as it works to invent a new leftist politics that can succeed in a moment of right-wing ascendancy. How it fares says much about where the left may be headed and the headwinds it faces, not just in France but throughout the West.

While once-robust labor unions have seen their numbers decline more drastically in France than in other European countries — around 8 percent of French workers belong to labor unions, compared with 35 percent in Italy or 18 percent in Germany — French unions remain strong. In part this is because recent labor activism has been buoyed by a newly resurgent leftist movement, La France Insoumise (L.F.I.), or “France Unbowed.” At the final pension-reform march in Paris last summer — a defanged one, to be sure, as the measure had already been made law — the area cordoned off for protesters gathering to march down the Boulevard des Invalides was draped with banners for L.F.I. “A different reform is possible, 60!” one proclaimed. Another demanded the founding of a new republic. One protester carried a giant marionette of Macron peeking out of a bright green garbage bin, an allusion to the scandal that followed the arrest of a woman at her home for an online post in which she called Macron “trash.” (The charges were later dropped.)