The Haute Vallée de Chevreuse Regional Natural Park, while far from being an extreme adventure destination, is nevertheless home to a variety of scenic hiking and biking opportunities among its wealth of forests, lakes, and rivers. To be honest, however, since the terrain is mostly flat, hiking here pretty much equates to long walks through wooded trails. Still, this is Paris, remember? When it comes to outdoor adventuring, one can't afford to be picky.
Though the Cevreuse Valley is often overlooked by those who travel southwest of the French capital to visit Versailles, its simple beauty allows you the opportunity to get lost exploring northern France while knowing somewhere up around the bend you'll come to another quaint country village. The medley of well-worn trails and paths here are easy to find and enjoyable to traverse, so pack your bike or just a lunch and a bottle of water and get to it.