The difference is not the light, it is the slot. In Paris a rooftop, a hotel salon or a department-store terrace opens up for a precise window, usually before the public is let in, and there is no next day. Whatever was not made inside the window will not exist.
In practice that means arriving with a written, ranked shot list, knowing which pictures have to exist whatever happens, and deciding on the spot rather than hoping for a second visit. On La Douce Heure the running order was fixed before going up on the roof, because the light was falling faster than the bar was being built.
There is also a physical constraint people underestimate: kit goes up and comes down in tight spaces, with no truck parked outside, so what you leave behind has to be decided too. One extra light that will not fit in the lift costs an hour of a three-hour window.