Hi Erin! Happy to report that dogs ARE welcome in Jardiland and other stores that sell pet food. I'm in there once a week with my dog here in the Loire Valley and it's no problem at all. I think we asked the first time just to make sure it was OK and they said absolutely. Granted, my dog is small and doesn't make any noise, but I'm sure it would be fine with your dog as well. They sell pet supplies...
Also, in general, at least where I live, shops are very welcoming (again I have a small well-behaved dog) when it comes to my dog. I run into the pharmacy with her, had a bank meeting the other day and she stayed at my feet the whole time under the chair and goes in the tabac, boulangerie and other places. Just on a leash, not in a travel bag or anything. As long as your dog doesn't cause any problems, I think it will be fine. As was previously mentioned, your dog can't go to the grocery store, but everything else should be fine. I find that once people at your local shops know you (and know how much you spend each month with them), they're more likely to ignore an almost invisible dog. ;-) So hopefully that makes you feel better.
That would NEVER fly at Duane Reade in NYC!
Good luck and feel free to ask me anything specific about dog stuff. Been through a lot of it already and know all about vet fees, etc.