No ink I have thus far used on this paper has feathered or bled through. It is excellent in that regard, and has a nice weight to it. However, it is extremely glossy, almost slick, in a way that I definitely did not anticipate. Rohrer and Klingner's old gold green ink on this paper almost feels like it doesn't take (It does. The low viscosity of the ink plus the smoothness of the paper just makes it feel like it won't.). Note that these observations are from a dip pen, not a fountain pen though. It's vastly better than regular printer paper. Just a warning that the surface is very slick.
Clairefontaine began manufacturing paper in 1858, and has since expanded to stationery items like sketchbooks, fine art pads, journals, and more. The company is located in the Vosges region of France, and remains notorious for the smoothness and quality of its paper.