France warned Sunday of "serious consequences" if Donald Trump moves to recognize Jerusalem as Israel's capital as representatives from 70 countries met in Paris to try to revive stalled Israeli-Palestinian peace efforts.

French President Francois Hollande hit out on Thursday at Russia's role in the ongoing siege of Aleppo, saying that Moscow had broken a promise to aid trapped civilians.

"Russia is making commitments that it is not keeping. There's a moment where you have to answer with action," Hollande told reporters as he arrived for an EU summit overshadowed by events in the besieged city where Syrian and Russian forces are forcing out rebels.

French President Francois Hollande on Wednesday joined calls for international observers to oversee the evacuation of civilians trapped under fire in the wrecked Syrian city of Aleppo.

IMF chief Christine Lagarde went on trial in France on Monday over a massive state payout to a flamboyant tycoon when she was finance minister, in a case that risks tarnishing her stellar career.

French far-right leader Marine Le Pen proposed Thursday that the children of illegal immigrants should be refused public school places as part of tough proposals to restrict state services.

French President Francois Hollande denounced on Wednesday "systematic obstruction" by Russia at the UN Security Council after the failure of a resolution calling for a seven-day ceasefire in the Syrian city of Aleppo.

French Prime Minister Manuel Valls has a reputation for never ducking a fight. But the tough-talking Socialist party modernizer may be about to embark on his biggest battle yet.

French Environment Minister Segolene Royal, representing her government at a tribute for Fidel Castro in Cuba, defended the late communist leader's human rights record on Saturday, questioning whether the regime imprisons dissidents.

Millions of French voters were casting ballots Sunday to pick the presidential candidate for the center-right Republicans party, with ex-premier Francois Fillon tipped to win and become favorite for next year's election.

French rightwing presidential favourite Francois Fillon struck a confident tone ahead of a final televised debate Thursday with his rival for the Republicans party nomination, Alain Juppe.