Even if your French is limited or nonexistent, saying a polite “Bonjour” to the shopkeeper when you enter a store will set you off on the right foot and probably earn you better service.
The main student quarter is the Latin Quarter around Place St. Michel, within sight of the Notre Dame across the river.
Smoking has been banned in French restaurants and cafes since 2008.
Fine pastries and fresh breads are affordable luxuries in Paris, even on a student budget.