French President Nicolas Sarkozy and Socialist rival Francois Hollande have clashed repeatedly in their only debate ahead of this Sunday's runoff election, which Mr. Hollande is expected to win.

During Wednesday's televised debate, Mr. Sarkozy and Mr. Hollande accused each other of lying during exchanges on economic policies. In campaigning, Mr. Hollande has blamed Mr. Sarkozy for France's unemployment rate of nearly 10 percent and called for sweeping changes to improve the country's public finances.

The lively debate occurred one day after far-right leader Marine Le Pen, who finished third in the first round of balloting last month, said she will not support either candidate in the runoff. In a speech, Le Pen said she will cast a blank ballot in protest and said it is up to her supporters to make their own decision.

Mr. Hollande emerged as the front-runner in the first-round vote and is ahead of Mr. Sarkozy in opinion polls. Mr. Sarkozy, who has been in office five years, has faced criticism for tough austerity measures aimed at reducing France's debt.

Mr. Hollande is a veteran politician who headed the Socialist Party for several years, but he has never held a top government post.