Northeast of Grenoble you can find a very tall waterfall with a height of 270 meters called Cascade de l’Oule. Cascade de l’Oule is located at the hamlet Montfort near Crolles in the region Alpes/Isère, France.
From Grenoble take the A41 to Chambery. Leave the A41 at exit 24 to Crolles. In Crolles drive further on road d1090 until you reach Montfort. Turn left after the roundabout to the Funiculaire (gps 45.299286, 5.898584). With the Funiculaire you can go up the mountain almost along the waterfall.
There is also a trail going to chateau de Montfort and further up the mountain to Cascade de l’Oule. The trail also goes up the mountain and ends at the end of the funicular.
Cascade de l’Oule is a tall waterfall with two single drops, short after each other of 100-150 meters. The waterfall is also a Via Ferrata, a trail where you can climb up along the waterfall, with climbing gear. In summertime the waterfall almost run dry but I think early in the season or after heavy rainfall is the best time to visit cascade de l’Oule.