Don't throw away your used métro tickets until you exit the métro, there are métro police who can and will fine you

Don't go to the Moulin Rouges unless you are rich and interested in a huge time-wasting, money-wasting, decidedly non-French experience

Don't get your portrait done in Montmartre unless you aren't picky

Don't be afraid to go into any place with live music and order just one beverage and stay as long as you want

Don't forget to say Bonjour! to every shopkeeper whose shop you enter (or Bonsoir, if it's evening)

Do not sit at a table that has silverware and a placemat already on it unless you plan to order a meal - if you want just cocktails/beverages and/or just one appetizer, sit at a table that is empty of utensils

Do not expect to have bar service prices if you sit down, beverages will cost more - and don't argue in English with the waiter about how unfair it is

Don't leave valuables lying on outdoor tables while you gawk around

Don't worry - the line to get inside Notre Dame goes fast (it's the line for the Towers that can be slow)

Don't worry if you eat a meal at a less-than-stellar restaurant because you need to save time

Don't prebuy tickets to the Louvre, it's the security line that takes the time, the ticket machines are fast

Don't think the buses run all night, at night the service changes - check the Noctilien schedule for that

Don't be without a paper map (they sell them at all the news kiosks and they have all the bus and métro info you could want)

Don't be an Ugly Traveler when inside a church - respect the space

Don't miss opportunities to get views (like the top of the (free) Escalator at the Pompidou or the one from on top of Galeries Lafayette or the one from the steps of the church at Montmartre and many others

Don't take the métro when you could walk...that's where the fun is