Rouen in Normandy is just far enough away from Paris on a fast train to escape its day-trippers but not so that it would break your alarm clock or budget.
Apart from the wondrous cathedral, it is one of the homes of impressionism. Visit a gallery or see the interesting old town where you can photograph, shop or people-watch from a cafe to your hearts' content.
www.rouentourisme.com
Google map: bit.ly/SwyqJV