Lateness is an epidemic in France. Maybe the laid back lifestyle and the 2 hour lunch break skews a person's perception of time. I'm not saying this is necessarily a bad thing, but it is certainly annoying for a person who grew up learning the importance of punctuality, like myself and many other Americans.
The French tolerate an excuse for those who are perpetually 15 minutes en retard. It is called le quart Français or "the French quarter hour". My professor in France warned us that this saying can be used for any region or city, for example le quart Lyonnais or le quart Parisien. Apparently, this excuse dates back to the day when there was only one bell tower in Lyon. The bells would chime every quarter hour and this was the only means of telling time in the town. So, a person would wait until the bells chimed to know what time it was and then it usually took them 15 minutes to get somewhere...
I question the authenticity this folklore is but even if it is true, I do believe it has had opportunity to be shaken for a couple hundred years now. The Swiss right next door have managed to create top-of-the-line watches but perhaps precision stays on the wrist. For those out there who can read French, I found some amusing blogs about the "French quarter hour":
In a French social scene, tardiness is even worse. It can be an awkward situation when an acquaintance invites you over at 9pm for dinner and when you show up at 9:15 expecting to apologize for tardiness, you are the only guest. This happened to me twice (shame on me) so I waited around rather embarrassed for a couple hours for other guests to show up. I had to learn that when a dinner party starts at 9 pm, you must add about 2 or 3 hours to that time in order to be "fashionably late". I much prefer plain language, where a dinner party that starts at 9 really starts at 9. After living in France, I really appreciate punctuality and have made sure I exhibit the same behavior for the sake of others.