But you are in France, and the French have different standards.
These include:
1) Do not wear a baseball cap.
2) Always address people as Monsieur, Madame or Mademoiselle.
3) Begin EVERY conversation (even if you're telling someone their house is on fire) with "Bonjour/bonsoir" as appropriate. And end by wishing everyone "au revoir, bonne journee/nuit." Don't just go in to a shop or bar and bark out your order.
4) Don't speak loudly in restaurants. In fact, don't speak loudly.
5) Let another person pass through a door first, and a man always gives way to a woman.
6) Do not make disparaging remarks about French military prowess, or they will drag you to the village war memorial and bang your head against it until you realise the extent of their losses in WW1. (OK, I made the last bit up, but you get the point. If you don't, just take a look at any war memorial. Every village, however small, has one.)
There are others, but, basically, err on the side of politeness. Oh, and master at least some basic French.