I stayed at the Martinez very end of 2011. I can confirm that it was FHR at the time. I had a very nice stay there, although I will say that it was fantastically priced (was low season) and that their restaurant was excellent. Not sure what will happen with that once Hyatt takes over management. My room was very pleasant. Service decent, location excellent. Breakfast was OK, not great, and has room for improvement. Probably a good fit for the Grand Hyatt brand.

As an FYI, the Concorde Lafayette is barely in Paris. It's all the way out at Porte de Maillot, and requires a metro (or very long walk) to get to the Arc de Triomphe. However, I think it is very inexpensive (at least now), so a good way to get points if that's important to you. Personally, I probably wouldn't want to stay there, even if it's done well post-renovation.

Hotel du Louvre has very nice location and post-renovation, could be very nice!