Re: "the Francophone hacker"
Knowing very little French myself, I asked Google... which says piétones means "pedestrianised" whereas piétonnes means "pedestrians". So Rues piétones would be streets that have been closed to vehicle traffic. Some cities and towns do this e.g. in a market area for certain hours in the afternoon/evening.
But as Google Translate isn't based on a language expert but Big Data, I have no idea if it's correct.