We have a reservation for lunch at l'Arpège, and need to go to Gare du Nord afterwards to catch a train. I began to read on blogs about dining at l'Arpège, and some people wrote it took 5 or 6 hours for lunch! We had planned to spend about 3.5 - 4 hours for lunch. Will it be too rushed? Should I cancel my reservation? Does lunch at 3-star restaurants all take that long?