The National Front not only came in first in the popular vote on Sunday with 28 percent of votes cast nationwide, it was leading races to govern six of France’s 13 regions, decisively in at least two.

Many factors combined to help Ms. Le Pen’s party in the first round of voting — the second will be held on Sunday — but the overwhelming message was one that the French elites have been reluctant to confront: The political rules that have governed the country for the past 25 years are being reshaped by a wave of nationalist right-wing populism familiar to voters in many other countries, not least fans of Donald J. Trump in the United States.

Just like Mr. Trump, Ms. Le Pen is shrewdly speaking to voters who feel economically strained, distant from leaders they perceive as elitist and out of touch, and angry or frightened by waves of immigration that they feel threaten their national identity and personal security. Her appeal, which helped her party win political control of a few French cities last year, seems to have only grown since the attacks in Paris last month that killed 130 people, giving the National Front a chance to establish greater credibility by governing key regions, including the area in the north around Calais that has been struggling all year to deal with an encampment of thousands of migrants.

She talks about the French “nation” and its “sovereignty” and making France once again proud of its “founding values” and “authentic Frenchness.” Such language takes aim at anyone who does not embrace assimilation into the French way of life.

In her victory speech on Sunday night she added the word “laicité” to the core French values of liberty, equality and fraternity. “Laicité” is loosely translated as secularism, but increasingly has come to mean eschewing any show of religious affiliation in public, which some critics see as a cover for anti-Muslim views. It is on the grounds of laicité that French Muslim women are barred from wearing head scarves in government jobs and in schools.