Lots of info on Paris attractions
Paris tourist site Paris metro tickets
Versailles
Line 12 to Line 8 [change at Concord then RER C at Invalides to Versailles Rive Gauche see: http://www.secretsofparis.com/histoire-de-france-versaille/ Book tickets in advance to save time .
Eiffel Tower
Getting tickets for Eiffel tower visits can be a challenge. The worst thing you can do is turn up and hope to get a tickets by standing in line….it could be a long wait!! Best is to buy tickets before you go. The tower website is the first place to check for availability and to buy tickets in advance . If that doesn’t have availability then try Viator. They often still have tickets when others don’t and offer skip the line tickets. While these will cost you more, you get a brief discussion of the tower’s history before going to the elevator through the priority entrance for access to all 3 levels, including summit.