The first to fourth arrondissements form the heart of Paris on the Seine River's right bank and include the two Parisian islands. Les Halles was the city's central market, covered in 1183. Read Zola's 1873 novel The Belly of Paris for a timeless picture of this unique setting unfortunately demolished in 1971 and replaced by a huge underground modern shopping center. Chatelet-Les-Halles is the world's largest underground transportation station. It serves three quarters of a million passengers daily. The Louvre Museum annually greets over eight million tourists, the most of any art museum in the word. Besides Mona Lisa and Venus de Milo it contains another four hundred thousand objects. Be sure to see the Tuileries Garden and the Comedie-Francaise. Nearby is the Hotel Ritz, the last stop for Dodi Al-Fayed and Princess Diana before their tragic 1997 demise.
The second arrondissement is home to Paris's remaining glazed commercial arcades. These often beautiful structures are Parisian adaptations of Oriental bazaars and souks that form a miniature city free from noise, traffic, and inclement weather in which window-shopping developed into yet another Parisian art form. They evolved (degenerated) into the suburban shopping center. Visit at least one arcade to get a taste of Paris in the days of old.
The Grand Boulevards form a long arc west to east from the Church of the Madeleine to the Bastille. Once the hangout for Paris's upper crust they still form a distinctive, often lively part of the city. The actual street name changes from Boulevard Madeleine, to five other names and finally to Boulevard St. Denis. Going east the boulevards traditionally get poorer and perhaps more interesting.
The third arrondissement contains the northern sector of the medieval Marais district while the fourth arrondissement contains the livelier southern part. The Marais was marshland first cleared in the Twelfth Century. In the Sixteenth Century the aristocracy built beautiful residences there. The Marais took a real hit when the court moved to Versailles. But luckily enough this area was not highly affected by Baron Haussmann's urban redevelopment. You should see the Carnavalet Museum, devoted to the history of Paris. Paris's oldest square, the Place des Vosges, was built by Henri IV as the Place Royale.
The Ile de la Cite (Cite Island) was already inhabited in the First Century B.C. by a Gallic tribe known as the Parisii who gave their name to the city. Georges Pompidou Centre built in the nineteen seventies near the Halles Market and the Marais contains a library, the National Modern Art Museum with works by Kandinsky, Matisse, Miro, Picasso, and much more. You either love the building or you hate it because of its very distinct (ugly) architecture with pipes on the outside.
Charles de Gaulle spoke from City Hall on August 25, 1944 when Paris was liberated. The rue des Francs-Bourgeois with its many fashion stores is one of the rare Paris streets open on Sunday. Even if you don't regularly tour churches see the French Gothic Notre Dame de Paris on the Ile de la Cite, one of the world's most beautiful churches. Construction took almost two centuries, and frankly was worth it. During the French Revolution, many of its treasures were either destroyed or plundered. Central Paris is home to several historic churches, but if you ask me none of them are in the same league as Notre Dame de Paris.