Um, well we're in Belgium so didn't have to suffer the exchange rate but France was definitely cheaper!
I lost track with UK prices, but our first shop cost 120 euros. This was for:
Salad (lots), fruit (lots), potatoes, onions, ham and cheese, butter, milk.
5 litre wine box plus 24 beers and a bottle of cognac. Bottled water and Orangina.
Pasta, pasta sauce, biscuits, crisps, bread, cereal.
A pizza, fish fingers, beef burgers, a load of kebabs, chops, chicken etc for bbqing.
I had a trolley FULL fwiw. We went for 2 weeks and I only did top up shoppng after that - more butter, ham, water, beer etc and we bought fresh bread every day.