Macron and Le Pen to square off in French pre-election TV debate

• Hollande urges French to reject Le Pen in presidential run-off vote
• France's Le Pen, evoking wartime Jewish arrests, re-opens old wounds
• EU lawmakers consider lifting Marine Le Pen's immunity over tweets
• France's Le Pen launches election bid with vow to fight globalization

Opinion polls still show Macron, 39, holding a strong lead of 20 points over the National Front's Le Pen with just four days to go to the final vote, in what is widely seen as France's most important election in decades.

Voters are choosing between Macron, a strongly Europe-minded ex-banker who wants to cut state regulations in the economy while protecting workers, and Le Pen, a eurosceptic who wants to ditch the euro currency and impose sharp curbs on immigration.

A combination picture shows portraits of candidates for the second round in the 2017 French presidential election, Marine Le Pen (L), French National Front (FN) political party leader, and Emmanuel Macron, head of the political movement En Marche!, (Onwards!). Picture taken March 2, 2017 (L) and April 13, 2017 (R). REUTERS/Charles Platiau

Macron finished only three points ahead of Le Pen in the first round on April 23, but he is widely expected now to pick the bulk of votes from the Socialists and the center-right whose candidates were eliminated.

Though Le Pen has a mountain to climb to catch Macron, the 2017 campaign for the Elysee has been packed with surprises, the exchanges between the two have become noticeably sharper and the 48-year-old National Front veteran has shown she is capable of catching him out with clever public relations maneuvering.

Macron warned he would not pull his punches in Wednesday night's televised encounter against a rival whose policies he says are dangerous for France.

"I am not going to employ invective. I am not going to use cliches or insults. I'll use hand-to-hand fighting to demonstrate that her ideas represent false solutions," he told BFM TV.

Le Pen, who portrays Macron as a candidate of high finance masquerading as a liberal, said: "I shall be defending my ideas. He will be defending the posture that he has adopted."

"His program seems to be very vague, but in reality it is a simple continuation of (Socialist President) Francois Hollande's government," she said in an interview with Reuters on Tuesday.