Paris - French far-right presidential candidate Marine Le Pen is facing new troubles, with fresh revelations in an investigation into her European Parliament assistants and scathing criticism from the UN human rights commissioner.The Parliament probe is among several legal issues hanging over France's April-May election, which is shaping up as a major test of growing nationalist sentiment across Europe.Investigative website Mediapart published excerpts from a European Commission fraud office report that said Le Pen admitted to irregularities in paycheques for one assistant targeted in the European Parliament probe.Le Pen, speaking on France Bleu radio on Friday, acknowledged settling an accounting problem with the Parliament, but insisted "there was nothing fictitious, no fake jobs or anything like this".French authorities are separately investigating the parliamentary assistants. The probes centre around suspicions that members of Le Pen's National Front party tricked the European Parliament out of several hundred thousand euros by using legislative aides for the party's political activity while they were on the parliament's payroll.‘Support for Le Pen’s idea a potential threat to world peace’Le Pen also reiterated accusations that the investigation is biased because it's led by the European Commission, "and you can imagine that I am not well-regarded by the commission." Le Pen has used her membership in the European Parliament as a forum to lobby against European unity and the shared euro currency, and reviving French national sovereignty is central to her presidential platform.Meanwhile, UN High Commissioner for Human Rights Zeid Ra'ad Al Hussein, in a blunt speech in Washington, called rising support for Le Pen's nationalist ideas a potential threat to world peace.Le Pen wrote Zeid an open letter last year in which she criticized international organizations as representing a "global hyper-class ... which scorns peoples, and thus human beings, their diversity and specific riches".Zeid countered Thursday that Le Pen's anti-immigrant party "manifests evident intolerance of diverse customs, beliefs and modes of thought".He also expressed concern that nationalist politicians like Le Pen seem "to feed off the threat of terrorism"."Can we be so reckless, so stupid, as to risk the future of humanity, simply for the sake of ballots?" he asked.