PARIS (Reuters) - French far right leader Marine Le Pen has increased her lead in the first round of France's presidential election, though she is still seen being beaten by a wide margin in the runoff, a BVA-Salesforce poll published on Thursday (Feb 23) showed.

The National Front head would win 27.5 per cent of the vote in the April 23 first round, up 2.5 percentage points from the last time the poll was conducted on Feb 4.

Independent centrist Emmanuel Macron was seen coming in second in the first round with 21 per cent of the vote, down one percentage point, followed by conservative Francois Fillon at 19 per cent, also down one percentage point.

In the May 7 runoff vote, Macron was seen beating Le Pen 61 per cent to 39 per cent while Fillon was seen winning the presidency with 55 per cent to 45 per cent.

However, because the poll was conducted on Sunday and Monday, it did not reflect the impact of the latest developments in the fast moving campaign, which has seen Fillon lose an early poll lead after being investigated over public funds he paid his family.

The poll did not take into account the possibility of veteran centrist Francois Bayrou running. On Wednesday, Bayrou announced that he would not run and would instead support Macron, which analysts say should give him a boost.

Also on Wednesday Le Pen's chief of staff was put under formal investigation as part of a probe into alleged misuse of EU funds to pay parliamentary assistants.

Le Pen denies any wrongdoing.