I will be in Paris in about a week. My plan for one of the days is to go to Sainte Chapelle in the morning - get there before it opens to minimize wait time. But I have also booked a walking tour in Montmartre at 11am & I think the only way I'll make it is if I can get a cab from Sainte Chapelle. Will that be possible? Would I find a cab? Or should I re-think my itinerary? Another option would be to try to see Sainte Chapelle late on a Saturday afternoon. Will I wait in line an hour at that time of day?