Francois Fillon's campaign for the French presidency faces new uncertainty after he abruptly cancelled a campaign stop at the country's premier farm fair and an investigation intensified into alleged fake parliamentary jobs for his family.

French far-right presidential candidate Marine Le Pen is facing more troubles, with fresh revelations in an investigation into her European Parliament assistants and criticism from the UN human rights commissioner.

French investigators have interviewed two children of conservative presidential candidate Francois Fillon in an embezzlement probe into paid, but allegedly fake, political jobs.

French presidential candidate Francois Fillon not only paid his wife for an allegedly fake job as a parliamentary aide, but also employed two of the couple's children for the same positions, a newspaper has reported.