Yes, seeing these gems was a real delight. The redesignated Gallery of Mineralogy of the National Museum of Natural History is not very large, but it is worth a visit, if you have an opportunity to visit Paris. It will be a nice complement to the visit of the Crown Jewels kept in the Louvre!
My impression was that the gems displayed at the Museum were smaller than what they looked on pictures, but the colour looked more intense. For instance, I had the impression, judging from pictures that the cushion-shaped emerald (visible on the left of the 2nd picture of my previous post, and on the bottom row of the new display setting in the Museum) was of rather low quality, with a lot of inclusions and a disappointing green colour. Actually, after having seen it, I can now say that it has a beautiful richly green colour, and that the inclusions are not really visible!