Russian President Vladimir Putin shakes hands with U.S. President Donald Trump as he arrives to attend a commemoration ceremony for Armistice Day, 100 years after the end of the First World War at the Arc de Triomphe, in Paris, France, November 11, 2018. Ludovic Marin/Pool via REUTERS

PARIS (Reuters) - Russian President Vladimir Putin and U.S. President Donald Trump greeted each other and shook hands at the Arc de Triomphe where world leaders gathered to mark the 100th anniversary of the Armistice that brought World War One to an end, Russian television showed.