Rue Longue has two medieval portes, one at each end. Here we see Porte Saint-Julien at the eastern end of the street - ie nearest to Italy. The original name was Porta Julia. With both entrances closed, the town was protected from invaders.
Later, in 1687, a chain barred the entrance and a tax had to be paid to the Count of Ventimiglia by merchants who wanted to sell their wares in Menton. This import duty was known as the 'droit de chaîne.'