All I can say about this place it is big and a sea of tourists. If you are a big city person this place is for you. Beautiful but once again a thick layer of pollution mills around it the whole time.
A few recommendations for Paris is to buy a guide on Paris and pick what you want. If you try to see everything you will be there for a long time. Stay away from the metro as much as possible as you can walk everywhere. There are a large amount of monuments and attractions close to one another. In between walking to these you see a lot of Paris. You can always get a rough bearing of where you are by the position of the Eiffel tower.
Have plenty of money as things are expensive and there are loads of tourist traps. This city never sleeps and has amazing night life and of course shops to suit everyone.
Have a look at the ‘Pompidou Centre’ - it is an amazingly interactive library with a huge range of multimedia stuff to do. You can learn 150 different languages there, listen to any music of your choice. If you don't like lines then go early in the morning or wait till night because the place is mostly free it is used to a maximum everyday. Plus an interesting building with all the building services on the outside to keep the floors open plan.