France's 10-year government bond yield gave up earlier falls to trade flat on the day at 1.10 percent, while safe-haven German Bund yields fell from 14-month highs

as the Fillon news refocused market attention on French election risks.

Fillon had been due to meet investigators on Wednesday but, in a surprise move, the meeting was brought forward by 24 hours - a move requested by Fillon's lawyer to spare him the full glare of the media.

Fillon made no public comment and his lawyer did not respond to telephone calls. Embezzlement of public funds can be punished by up to 10 years in jail and a 1 million euro fine.

Conservative newspaper Le Figaro quoted Fillon as telling the judges: "You decided to call me for questioning hurriedly for things that date back, in some cases, 20 years," re-affirming that his wife Penelope did genuine work as his parliamentary assistant.

Fillon's campaign staff confirmed the comments.

Under French law, being put under formal investigation means there is "serious or consistent evidence" that points to probable involvement of a suspect in a crime.

It is a step towards a trial, but many investigations have been dropped without going to court.