PARIS — Travelers with the time and means for top-notch trips are in for a treat. Marc Jacobs’ fall collection for Louis Vuitton is perfect for them, a surprisingly discreet combination of luxury and practicality. That means pastel leather motorcycle pants, lightweight knits and a fab group of coats, including leather bombers or blousons and a flyaway wool peajacket, lined in mink. Here, the fur-hooded parka over a simple sweater and skirt. For more on the season, see pages 4 to 7.