Travel Ideas/ Must sees (feb18) (Paris)

Hello All,
A friend and I are meeting in Paris and plan on staying in Paris for 4 to 5 nights and then plan on exploring the countryside for 4 to 5 days (by train and/or car). We are open to any suggestions. We are pretty laid-back travelers who both enjoy meeting new people and seeing new places (open to less touristy places as well). Thanks for your help. =)