According to an Elabe poll for BFM TV and L'Express, Macron will get 62 percent of the votes in the second round compared to 38 percent for Le Pen, an increase of three points for the centrist candidate compared to his projected score in the last Elabe poll.
The showing is Macron's best in a voting survey by a major polling organisation since nine other candidates were eliminated in the first round on April 23.
The survey was carried out after a rancorous final televised debate between the two contenders on Wednesday, which Macron was seen by French viewers as having won, according to two polls.
Macron's strong showing in the debate and another poll this week that showed his En Marche! (Onwards!) political movement was likely to emerge as the biggest party in the June legislative elections as well have lifted the mood among investors who had worried about the upheaval a Le Pen victory could cause.
On Thursday, the premium investors demand to hold French bonds over German ones reached its narrowest point in six months, reflecting perceptions that Le Pen had missed her last chance to unseat Macron.
The anti-immigration, anti-EU Le Pen was not giving up. "My goal is to win this presidential election," she said on RTL radio. "The choices of Mr. Macron are choices which would lead to the end of our country as we know it, the end by being submerged by migration, which he will not oppose given his submission to the policy of Mrs (German Chancellor Angela) Merkel, the choice of the social devastation of deregulation, of ultra-flexibility which will mean war by everybody against everybody else."