PARIS - An apparent threat by far-right leader Marine le Pen to punish state employees who "persecute" political opponents may have eroded her support, according to a poll which found her first-round lead in France's presidential election slipping.The poll of voting intentions by research firm BVA found Le Pen garnering 26 percent of the votes in April's first round, down 1.5 percent from the last BVA poll on Feb. 23.It found independent centrist Emmanuel Macron gaining momentum, rising three points to 24 percent.Conservative rival Francois Fillon remained at 19 percent and would therefore be eliminated from a second-round runoff to be held in May, in which Macron was seen defeating Le Pen by 62 percent to her 38.Another poll, by Odoxa, on Friday showed Macron finishing ahead of Le Pen in the opening round.BVA said Le Pen had likely lost support because of comments at a rally in Nantes last week in which she appeared to threaten to punish government employees who would "persecute" political opponents."I want to tell public sector workers who are asked by a desperate political staff to use the powers of the state to keep tabs on opponents, to organise persecution, low blows and state cabals against them, to keep out of participating in such excesses," she said."In a few weeks, this government will have been swept away by the election. But these civil servants will have to take responsibility for these illegal methods, because they are illegal and are putting their own responsibility at stake," she added.Le Pen refused to attend a summons for questioning by police last month over allegations that she made illegal EU payments to her staff and her lawyer said on Friday she had also refused to attend a summons by judges over the allegations. Some of her aides have been put under formal investigation over the affair.