A place with plenty of 'must-see' monuments but foresee the problems in order to make your trip efficient.
1. Louvre museum is closed on Tuesdays but seems to be open until 21:30hrs on Wednesdays and Fridays. Plan a full day for this museum. It is extraordinary.
2. Do not trust Paris railway. On my day of arrival in CDG airport, RER-B line took around 2 hours extra to reach Gare-du-Nord due to some security reasons. Trains were plying in the opposite direction.
3. I returned from Venezia to Paris-Bercy railway station and took metro-RER-B to go to Gare-du-Nord. It took 1 hour for the railway to tell (verbally; not through public address) that RER-B line was closed.
4. Visit to Versailles palace by RER-C was miserable as the line was closed. Utter confusion, I reached place at 16:00hrs by alternate routes. Versailles palace needs atleast half-a-day but I could see only for 2 hours.
5. Tourist information counters are seldom seen, even then they are not manned all the time and the information are not sufficiently provided. This is one of the weekest areas.
6. It is a long queue to see Notredam Cathedral - topside (main cathedral area is free entrance and no big rush). The top entrance was closed between 13:00 to 14:40hrs. But the queue was still waiting.
7. Plan your return to airport suffiently early to anticipate railway hurdles.
8. Metro buses are more convenient than railway but one should understand the easy routes.
With all these struggles, Paris is a place to visit. Anticipate

paris is hands-down the most amazing city we've been to. My husband and I love to travel and have been all over, but for some reason beyond my grasp we just hadn't visited Paris. Give yourself at least 5 days - you can't possibly enjoy the city in a weekend visit only. If you do visit for just a couple days, I'd say skip the museums (and the long lines) and take a quick tour the first day...then lounge around the city eating and drinking wine. We loved the bike tour - FAT TIRE was the name of the company. Ile St. Louis is a blast during the day and the Montmartre area is fabulous at night. Oh hell, it's all fabulous! ...by the way, I'm not sure where this misconception comes in about Parisians dressing up all the time - we felt over-dressed every night at dinner. Everyone was SO casual.

We visited Paris from the 28th June to 3rd July 2009 to celebrate our 10th wedding anniversary. It was the best holiday we have ever had. Paris blew us away.
We stayed in an area of Paris called La Marais (The Marshes). We were in an appartment that was over 400 years old and had its own courtyard. To give you an indication of the location:
Ctre Georges Pompidou - 2 min walk
Notre Dame - <10 min walk
Louvre - 10 min walk
Place de la Bastille - 15 min walk
La Defence 20 mins on Metro from Hotel de Ville. Incredible a must see.

We didnt go into any museums and that may sound strange but we just walked around soaking up the sights, the sounds and the incredible architecture.

I could type for a week on Paris but I cant praise it enough.
2 negatives - 1 was Montmartre. We thought it was a dump. Sacre Coeur was stunning but it was over run with "lucky - luckys" selling cheap tat. The shops were full of the same cheap nasty crap. We got off the metro at Chateau Rouge and felt really uncomfortable walking around. Avoid it. There are som many other beautiful places to see.

2nd negative was the show Moulin Rouge. What a load of over hyped tacky cheap trash. Its like that tv show Eurotrash only not funny and over a €100 a ticket. Ok the women were as good as naked but they were homogenous. The smiles on there faces were set with botox and the dancing was mechanical and over rehearsed. If any one has seen the daily parades in Disneyland Paris well Moulin Rouge is rubbish in comparisson.
We went as a special treat for our 10th wedding anniversary and as soon as it started we loooked at each other and shook our heads.

I used Paris Attitude to rent an apartment for 1 week holiday. On arrival, after 30 hours of travel, the person at the apartment to greet me told me I had to pay an extra 50 euros as I had arrived on a Sunday. I paid it but advised I would check my contract for this clause. When I checked, there was no such clause. I emailed Paris Attitude twice with no response at all. I have been home 3 weeks now and I have had no response to getting my 50 euros back. I would never use this company again and certainly not apartment number 3378. They have ripped me off with no comeback what so ever. Stupid me for handing over the money but I was tired, wanted to get into the apartment and thought the money would be returned when Ichecked the contract. Shame on you Paris Attitude and landlord of #3378