Whilst we were in France this year I discovered a few little things that may be helpful to you.
1. Supermarket trolleys don't have straps on. So if you have a toddler/baby that won't sit still it's best to bring along their pushchair or have them in a carrier strapped to you.
2. Proper high chairs seem to be few and far between in restaurants. And if they did have one it may not have straps. Quite a few restaurants seemed to have booster seats but there was no strap to be seen not even one to attach the booster seat to the chair. I was so glad I took our Totseat with us, I would definitely recommend taking one or something similar with you.
3. If you're going to be purchasing nappies, Pampers are SO expensive so go for a cheaper brand. The first time we travelled we purchased Carrefour own brand, these worked very well. This year we purchased Pommette, these weren't so good.
4. Food wise, the selection of baby food in the supermarkets were amazing (and looked rather good), there was loads of fruit purees as well as main meals. There was just not any baby snacks, and I couldn't even find any little packs of raisins. As I didn't know what there would be I did take loads of toddler snacks for Ben like Carrot Stick crisps and some little fruit snacks, so I was prepared.
5. The milk colours are different in France, whole milk is red. And we couldn't find any whole milk in any of the service stations on the way down, or on the P&O Ferry crossing either. We didn't even bother looking on the journey home!