For a first-time visitor in 2026, the "sweet spot" for Paris is 4 to 5 days. This duration allows you to see the "Big Three" (Eiffel Tower, Louvre, and Notre Dame) without feeling like you are in a constant race against the clock. A 5-day itinerary provides enough flexibility to dedicate a full day to Montmartre and the Sacré-Cœur, a half-day for the Musée d'Orsay, and an evening for a Seine River cruise. It also leaves room for a day trip to the Palace of Versailles or Disneyland Paris, which are both about 45–60 minutes away by train. If you only stay for 2 or 3 days, you will likely spend most of your time in transit or in long museum queues, missing out on the essential Parisian experience of "flâner"—aimlessly wandering through charming neighborhoods like Le Marais. While you could spend a lifetime exploring the city, 5 days ensures you leave feeling like you have truly experienced the "City of Light" rather than just checking off a few items from a bucket list.