01 Versailles Palace & Gardens
The single biggest decision in a Paris itinerary, because Versailles eats a whole day and the cheap tickets do not include the part people remember. Entry starts at €58; the bike-and-market tours that top our ranking cost more and consistently rate near 4.9, largely because they get you into the gardens early and out of the queue at the gate. Go on a Tuesday if you can, and never on the first Sunday of the month.
02 The Louvre
Timed entry from €50, and the slot you pick matters more than the ticket type: the Denon wing at 10am is the crush everyone complains about, and the same rooms at 5pm are half empty. Guided visits are worth it only if you want the collection explained; for the Mona Lisa and out, a plain timed ticket does the same job faster.
03 Musée d'Orsay
The museum Parisians send you to instead, and the one where a guide earns their fee: entry from €20, small-group tours rate highest of any museum product in the city. The building is a converted railway station and the impressionist floor is at the top, so start there and work down.
04 Eiffel Tower
Tickets from €25, and the summit sells out weeks ahead between May and September while the second floor stays available. Reserved-access tours hold their own allocation and are the fallback once the official quota is gone. The view of the tower is from Trocadéro; the view from it is of everything else.