Sales Tax On Comps

I got a room at a Paris recently and paid for the room with my TR comp points. I was very surprised that the sales tax was not removed, I was under the impression that comped items were not subject to tax. Can anyone provide some insight here? Was I right that the tax should have been removed or were they right? Also the room rate was heavily discounted based on my play, from $200 to $50, so why was only the $50 taxed if $200 is the civilian rate?

Are you sure it wasn't adjusted off? I believe on my last one it showed sales tax but my points were not used.