Originally Posted by Carolina2Cali

I don't know where you're from, and I don't know the law if I am being frank, but the libertarian in me wants to reply. In America, we separate taxes from the product cost so consumers/citizens are reminded every single day of exactly what they are paying for... including in hotels and flights, everything must be shown broken out. That's direct consumer taxes anyway... of course if corporations are taxed on the backend, they may up their prices, but you WON'T necessarily see the tax. Without knowing French law or even US Airline law, it still seems to me that taxes are taxes, and if they can be easily wiped off of paper because the product isn't happening... in this case, landing on French soil, they should ABSOLUTELY be refunded and no airline has a right to keep them as some sort of lost revenue makeup for offering an alternative to keep the sale and happy customer.

EDIT: Adding this - that is why you must pay for taxes when booking on mile award redemptions, and cannot use miles to pay for them.