Advice #1: We took the subway to our hotel from Gard du Nord Eurostar, lots of stairs instead of escalators, so we returned via TAXI.
Advice #2: They give you bread without butter and water without ice, but just go along with it!!!
Advice #3: The Latin Quarter has an area called Little Athens, just a few streets FILLED with restaurants of all ethnicities. Skewers of meat, seafood, etc.... fondue places,,, all sorts of great food and not very expensive. Food is not expensive, drinks are not cheap. For the price, drink wine instead of water or soda.