Velib is Paris free bike network. There are about 20 000 bikes available in the City that you can take at a station like this one and leave at any station you want. You only have to subscribe for 1 day (1 euro) 1 week or one year (that's my subscription). Then the bike is free for 30 minutes which gives time to easily go from one point to another. If you need more time you just need to park you bike, wait a few minutes and take another bike for again 30 minutes. If you want to know more about Velib you can go on the official Velib website.
The BNF for Bibliothèque Nationale de France is the National Library also called François Mitterand Library (former French President). It's in the south east of the city, an area that has been completely re-built these last years. The library is made of 4 towers looking like open books with a large garden in the middle.
The boats on the river banks offer cafés and concerts like the red one called "Bateau Phare".
The " Red children market" as we can translate it, is the oldest market place in Paris. The name comes from an orphanage of the 16th century located there which used to dress in red the children that they took care of. When the orphanage closed in 1777, the place became a market.
Now you can find there a compact indoor food market with a small iron-gate entrance that’s easy to miss if you aren’t looking for it. The nice thing about the market is that many of the stands sell fresh prepared food that you can eat on tables spread out through the market.
The famous Moulin Rouge cabaret, where we still can see "Cancan"danse. In fact I've never been to a show there but I like the building. I also love the Baz Luhrmann movie taking place in an imaginary Moulin Rouge.