If Mr. Trump is keeping score, however, as he most assuredly is, he would have to admit the Trump wave has yet to rise. In Austria in December, voters narrowly chose a Green Party candidate over one from the far-right Freedom Party as president. In the Netherlands last month, the Party of Freedom fell short of being the largest party in the House of Representatives. Some European analysts speak of a Trump backlash.

Ms. Le Pen still has a chance of winning. But France’s presidential election has become a fragmented affair, with her and three other candidates — a conventional conservative; a centrist, a former banker; and a rising leftist — all vying to emerge from the pack in a campaign that has been driven as much by concerns over the economy as terrorism and security. Voters will choose among 11 candidates in the first round of national voting on Sunday.

Moreover, Mr. Trump is unpopular in France, and as a result, Ms. Le Pen does not invoke his name on the campaign trail, even if his campaign is in some ways a blueprint for hers.

There is little doubt he favors Ms. Le Pen. In an interview with The Associated Press, Mr. Trump said Friday that though he would not endorse her, the fatal shooting of a police officer on the Champs-Élysées, an act claimed by the Islamic State, would help her because she was the candidate who is “strongest on borders, and she’s the strongest on what’s been going on in France.”

Ms. Le Pen seized on the attack to turn the election into a referendum on what she calls “radical Islam.”

She and Mr. Trump do not know each other, but early on, she clearly sought to tie herself to his success. After his election, Ms. Le Pen exulted that it had “made possible what had previously been impossible.” In January, during the transition, Ms. Le Pen was photographed having coffee at the Trump Tower cafe, prompting a flurry of rumors about whether she was in Manhattan to meet the president-elect. (Mr. Trump’s aides denied it.)