The Rockefeller Center Librairie de France closed a few years back, but perhaps all is not lost ... they've announced that:
The Cultural Services of the French Embassy is currently working on a project to open a new French bookstore to be located on the Upper East Side of New York CityRespond to their survey -- which presumably will give them a better idea of whether or not this is a viable idea. (I have my doubts but am keeping my fingers crossed.)