No idea, I've never heard of them before. Paul is pretty much present everywhere in France (even at some motorway service stations) so it's convenient when there is nothing else in the neighborhood, hence why I prefer them as a chain solution.
Though the first thing I did when I arrived in Paris in June (to visit the Musée de l'air et de l'espace) was look for a bakery with fresh croissants. when in France I suppose ...