I've been there once - we rode out on the train - and did NOT have time to see even half of it. If you could plan it, spend a night in the area in order to have a second day. It is truly a world landmark, and the gardens - lovely and enormous. The problems in seeing it all in one day: you have to join a tour in your language to see just one part; then another tour for another part, etc; perhaps each part is only two or three times a day. Also, Marie Antoinette's farm and house are fascinating, but, again, you have to ride a little bus to get there. You can just look around parts of it, such as the grounds, but the enormous palace is best seen with a guide.
I think we saw ALL the art museums in Paris. Some famous artists have their own museums. I loved going to the concerts in the churches there - wonderful classical selections. Two days at the Louvre. Notre Dame has organ concerts, besides their services.
I went to France twice, and toured Fountanbleu, and each tour was completely different. It didn't compare to Versailles in may opinion. The street in Paris with all the famous fashion designers on it is interesting - I was just window shopping! The large department stores are beautiful inside to see (can't remember the names) but worthwhile. I need to go look up my Paris stuff - name data not working today in my brain.
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