It’s actually not all that uncommon. People let their hair down here once in a while. I’ve been to jams at pubs/cafés wherein the proprietor locks the door after the official closing time and we all just keep playing as long as the party is going.
Much like California, this is a very special place. Though, like California, it’s often easier for someone new to see how special it is. You are welcome to come to France and experience the life any time.