If you are traveling to Paris and looking for a beautiful castle or historical site with a very few tourists, you should really consider this place: Maintenon! The castle of Maintenon is not that famous, and even a few french visited it. It's really strange because, this castle is very well preserved, and hides a huge history. You maybe hear about Madame de Maintenon, which one of Louis XIV's mistress ? This was her castle, and the king visited her several times !
But the castle itself worth the visit ! The local administration recently payed attention to maintain the beauty of the castle, and because of the quite few tourists there, it will be very easy to enjoy the moments there! And some of the rooms inside are really impressive: no doubt, Louis XIV was there!
As I said, it s quite easy to go to Maintenon from Paris: you can take the train! There is daily trains from gare de montparnasse (line 13) almost every hour to Chartres. You have to take one of them (regional trains are called TER) and simply stop at Maintenon station (40 minutes from Paris). From the train station, you will have to walk a bit! Prices are around 7 euros, but at least there won t be long waiting lines :) In my opinion, you can take one day from Paris and visit Chartres (Unesco cathedrale + nice restaurants) and Maintenon in the same day!