All the Renault names have an element of French language to them though to give them that sense of Parisien fashion. I think that is what they use to differentiate from other cars.
Citroen used to do the same but their cars began with the letter X, which might be extremely pronouncable in French, but Irish people can't really get their tongues around Xsara.
I think that car names in general tend to be fairly awful when taken away from the car itself. The hope is that the car becomes bigger than it's name. Like the 'Kraft durch Freude wagen'.