Even on a tight schedule, Montmartre earns the hours.
Allow 2–3 hrs.
Wander the back lanes (Rue de l'Abreuvoir, the vineyard, the last windmills) and Montmartre is romantic and villagey; cross into Place du Tertre and it's caricature artists and overpriced cafés. The trick is to climb early and steer clear of the obvious square.