It takes a lot of time to see all the places of interest in Paris, but there are some Paris attractions that are worth seeing first of all.
There are roughly 1800 historic places (squares and streets, bridges and architectural monuments, palaces and cathedrals) and 130 museums, 14 of which are free, in Paris. It is impossible to see them all at a time.
The Eiffel Tower, the most famous tourist attraction, is the first thing that any tourist will want to see. It is situated on the Champ de Mars. It is 1,063 ft tall. If you want to go up the tower, you will have to climb almost 2 thousand stairs. There are elevators in the tower for those who are not ready for that.
Other main Paris attractions are situated on the Axe Historique (also known as the Voie Triomphale or the Voie Royale). The Axe Historique starts with the Louvre, that is in the very center of Paris. The Louvre is a former royal palace and today it is one of the largest museums in the world. The Equestrian Statue of King Louis XIV is the starting point of the Axe Historique. The Louvre is open every day (except Tuesday) from 9 a.m. to 6 p.m. and until 9:45 p.m. on Wednesday and Friday.
The next point of the Axe Historique is the Tuileries Garden which is situated between the Seine, the Rue de Rivoli, the Place de la Concorde and the Louvre. It's the most ancient and significant French formal garden. You can see the Arc de Triomphe du Carrousel in front of the Tuileries Garden.
Famous Avenue des Champs-Élysées is one of the main roads of Paris and lies behind the Tuileries Garden. It starts with the Luxor Obelisk on the Place de la Concorde and finishes at the Arc de Triomphe de l'Étoile. The Avenue des Champs-Élysées is almost 6500 ft long.
When you enjoy the Arc de Triomphe de l'Étoile, you can go farther and see La Grande Arche de la Défense in Paris' modern business district. It was built in the late 80s and is the 20th century version of the Arc de Triomphe.
Nevertheless the Voie Triomphale is not a historic center of Paris. If you want to see the historic center of the city, you should visit the Île de la Cité. The Île de la Cité is connected to both banks of the Seine and the Île Saint-Louis by 9 bridges.
The main attraction of the island is Notre-Dame de Paris, geographical and spiritual heart of the city. Other places of interest of the Île de la Cité are the Sainte-Chapelle, the Place Dauphine, the Hôtel-Dieu de Paris (the oldest hospital in Paris) and the Conciergerie (former prison and royal palace).
These are not surely all you can see in Paris. If you have time and desire, you can visit Tour Maine-Montparnasse and Sacré-Cœur, the Panthéon and Les Invalides (the Musée de l'Armée), the Cité des Sciences et de l'Industrie (a large science museum) and Centre Georges Pompidou.