Parcours Nature Fier et Erbe
After I reached the Passerelles neighbourhood in Cran-Gévrier and the end of the path along the Thiou river, I kept walking on the road until the start of the Parcours Nature Fier et Erbe (Fier & Erbe Nature Trail). It is a path in the forest that follows the course of the Fier river at first, then the Erbe, a brook that flows into the Fier. Here is a map.