François Fillon, Candidate in French Election, Vows to Run Despite Inquirybr PARIS — François Fillon, the conservative candidate, defiantly declared on Wednesdaybr that he would not abandon his bid for the French presidency, four days after prosecutors said they were opening a formal investigation into his possible misuse of public funds.br Le Pen would lead in the first round, which is often used by voters to vent frustrations, andbr that she would face either Mr. Fillon or Mr. Macron in the second round, which this year would be held May 7.br By ADAM NOSSITER and DAN BILEFSKYMARCH 1, 2017br Mr. Fillon, the center-right candidate for the French presidency, vowed to staybr in the race even as he faces charges in a widening embezzlement investigation.br If Mr. Fillon had dropped out of the race, the greatest beneficiaries would most likely have been Emmanuel Macron, 39, who has started his own political movementbr and who favors keeping the country in the European Union; and Marine Le Pen, a right-wing populist whose potent cocktail of protectionist economic policies and right-wing nationalism has resonated with voters.br Mr. Fillon’s campaign announced earlier in the daybr that he would not be visiting the annual Salon International de l’Agriculture in Paris, normally an obligatory stop for politicians seeking to draw support from France’s important farming sector, prompting widespread speculation that he would pull out of the race.br The scandal surrounding Mr. Fillon escalated when French prosecutors said they had opened a full-scale investigationbr into whether he had embezzled public funds, threatening to make his candidacy increasingly untenable.