Brimming with cultural and historical beauty, Paris is the city you can't get enough of. The plethora of landmarks, and museums, but also the elegant architecture that characterizes the city, both Gothic and Hausmannian, inevitably absorb one. However, owing to its small size and incredibly accessible public transportation system, it is possible to gain the essence of the city briskly. That is, even if you only have 48 hours to spend!
Here's the ultimate 48-hours-in-Paris itinerary:

Day 1
Morning:
Visit the famous Louvre museum. Ideally, get the Louvre Museum Skip the Line Ticket (guarantee entrance within 30 minutes).
tips: Go prepared. Know what you want to see. Le Louvre is massive, and you need several days to view everything in detail.
Walk around the Tuileries gardens, and get a hot chocolate (to-go) from Angelina.
Early Afternoon:
Visit the Marais. Before walking around the area, which is a must, enjoy lunch. There are not only plenty of restaurants and cafes in the district but also stands that offer a number of delicious treats.
After exploring Le Marais, find some time to walk to Centre Pompidou. This is a modern art museum at the heart of Paris, and even if you are not interested in viewing their collection, you should still devote a minute or two to appreciate its architectural elements on the outside.
Walk through Île de la Cité (the island of Paris) to the Quartier Latin of the city.
- In the Île de la Cité, you will find the Cathédrale Notre-Dame. Feel free to take a stroll inside, if it is open.
- Exiting the island, you will find yourself near Shakespeare and Company, the popular bookstore. Enter if you are a book lover.