I have just flown LHR - CDG - LHR on the Air France A380. This was only to fly the A380 (sad I know), but will more than likely be the only time I will fly to CDG. Terminal 2E is one of the most expensive departure halls I have ever been to. Most restaurants were charging around 8-9 euros for a small piece of cake. The restaurant upstairs, around 10 euros for a piece of pizza/lasagne etc. We spent 15 euros for a couple of chocolate bars and packet of crisps (healthy option).
The positives though, Heathrow couldn't have been easier, staff very polite, no queues at check in, or security, and plenty of places to eat/drink at reasonable prices. Air France itself were great, we may have been lucky as the A380 was more of a promotion flight for Air France though.