Recognisable by their fluorescent high-visibility jackets, nine “traffic marshals” are in charge of road safety around the site for the duration of the construction work.  Their role is to protect pedestrians, especially in the key area around the school and creche in Rue de l’Arbre-Sec, while further away in Rue de Coligny, lines of lorries in front of the Louvre await the green light from a traffic marshal who, together with a colleague from the neighbouring Halles, choreographs a “ballet of the engines” between the two construction sites.