A few nights ago, I went to dinner with my friend at a no-reservations restaurant in the 13th arrondissement called Chez Gladines. The place was as densely packed as a restaurant could be. When our spot in the queue opened up, we ended up being seated at the same table as two other diners. Having a private conversation would have been impossible. As it turned out, our discussion included them, in both français and English.
During my many walks throughout Paris, I observe many people dining alone, which is a far more common occurrence than in the United States.
I have gotten much better at biking and refraining from riding on the extremely wide sidewalks. These sidewalks are often wide enough that they could serve as a two-lane road for cars, but I have been admonished that riding among pedestrians is frowned upon and could even merit a police citation.
People drink openly in the streets. I saw one young woman with her friends sharing a bottle of wine with plastic cups in the middle of the street. If there any open-container laws in this city, then they are totally ignored.
I see more smoking indoors. In the New York City and San Francisco, such action would bear little tolerance. I was told there are laws against it in Paris, but again, they are loosely enforced. An enclosed tent or canopy that is an extension of the restaurant may not even technically count as indoors.
In some trains, there is a button on the door to open it when the car comes to a stop. The last time I rode the train, I hesitated, waiting for the door to open. The exasperated girl next to me pushed the button and went on her way.