To save time, take the metro or bus to get around the city. A day pass will cost you around €10 and will allow you to access unlimited rides on metros, buses, and trams. Taxis are also an option and typically cost €1.50 per kilometer; however, these can be expensive and prone to traffic. Keep in mind that Paris is a large city and walking from place to place may not be feasible.
If you have more time in Paris, consider visiting the Musée d'Orsay or the Palace of Versailles. If you have less time, cut down the number of activities to two and, in case Eiffel Tower is closed, check out the Arc de Triomphe instead, for spectacular views of Paris.