http://www.lepoint.fr/faits-divers/paris-un-policier-agresse-sur-le-parvis-de-notre-dame-l-assaillant-blesse-06-06-2017-2133236_2627.php
Per above link, perp also had 3 knives on him. And a computer.
Perp also managed to injure a soldier/officer, striking the good guy in the head with the hammer.
How the heck was the perp allowed to get that close?!