US President Donald Trump waded into France's presidential election on Friday, tweeting that he expected the killing of a policeman in central Paris to have an impact on Sunday's vote. Islamic State claimed responsibility for the fatal shooting late on Thursday of a French policeman on the Champs Elysees by a French national who lived in Paris. 'Another terrorist attack in Paris. The people of France will not take much more of this. Will have a big effect on presidential election!' Trump said on Twitter. The attack prompted far-right presidential candidate Marine Le Pen to say on Friday that France should reinstate border checks and expel foreigners who are on the watch lists of intelligence services.