TOULOUSE, France — One man gives shivers to banks, businesspeople and the bourgeoisie. One man has been rising rapidly in polls, threatening the front-runners a week before the first round in France’s presidential election. One man has suddenly turned the French contest, locked for months between two favorites, into a four-man race.

That one man is Jean-Luc Mélenchon, admirer of Fidel Castro and Hugo Chávez, sworn enemy of NATO and high finance, and candidate of his own “France Unsubjugated” movement, who has been drawing tens of thousands to his rallies, especially the young, as he did here Sunday at Toulouse on the banks of the Garonne River. They came to hear a veteran French politician give them a dousing of old-fashioned Robin Hood-revolutionary rhetoric, with promises to tax the rich hard, give to the poor and start a “citizen revolution.”

The formula, delivered in fiery anticapitalist phrases, and peppered with learned philosophical abstractions, has put him within spitting distance of earning a spot in the election’s decisive second round on May 7.

“Mélenchon: The Insane Program of the French Chávez,” the right-leaning newspaper Figaro blared in a front-page headline last week. The candidate was delighted by this jittery jab.