TOPSHOT - A woman places a flower at the spot where a shooting occured on the Champs Elysees avenue in Paris, on April 21, 2017 a day after a gunman opened fire on police on the avenue, killing a policeman and wounding two others in an attack claimed by the Islamic State group just days before the first round of the presidential election. / AFP PHOTO / PHILIPPE LOPEZ        (Photo credit should read PHILIPPE LOPEZ/AFP/Getty Images)