With the motives of the Champs-Elysées gunman considered terror-related, the timing just three days before the first round of the French presidential elections and during a prime time TV "debate" between all 11 official candidates clearly suggests that extremists are seeking to influence the tone of the debate - and perhaps its outcome.

If that was the aim, it was a success, as two candidates - Marine Le Pen, the far-Right Front National leader, and conservative François Fillon - cancelled visits on Friday - the final day of the campaign.

As they learned of the attack while on air, all the runners adapted their conclusions to pledge to protect the French. "Enough of laxism, enough of naivety," said Ms Le Pen in hers. "The fight against terrorism must be the absolute priority of the next French president," said Mr Fillon, who proposed arresting all suspects on an "S" watch list, like the gunman.