Chicago doesn't have year-round lovely weather, so it's a treat for us Windy Citiers to dine out at one of those lovely places with open french doors during the summer.
Now, let's make a key distinction here: french doors are actually more like big windows that happen to swing open when weather permits.
A door is the opening through which you enter and exit a room, house, or place of business.
When it's time to leave, lovely people, exit through the second one. How did you enter the restaurant? My guess is you didn't climb through the french doors, disturbing the nice people eating nearby. Exit through the regular door, same as you came in, and don't disturb the nice folks enjoying their meals.
To walk to the front of the restaurant, cut through tables, and then step out through the french doors is plain boorish and rude. Don't do it.