Just returned from 2 weeks in France. My wife and I have a small (7 lb.) dog.
Restaurants were wonderful. never an issue about bringing in the dog. Restaurants seem to be universally welcoming to dogs. We dined in one small bistro with 16 seats. By the time 12 people were seated, there were 4 dogs in the restaurant.
However, our experience in museums was horrible. Unless you are a blind person with a service dog, the dog will not be allowed in. Same for taxis in Paris.
Dogs in the Paris Metro must be in a carrier.