This trail runs through a large part of the Montjoie Valley starting at the town center of Saint-Gervais-les-Bains. You can have a quick look at the main church, the Eglise Saint-Gervais et Saint-Protais before setting of on the trail southwards. The trail largely follows the Bonnant River as it snakes its way to through the Montjoie Valley. On the way you will be passing multiple little hamlets and farm houses. Occassionally you wil venture a bit more inland away from the river with a few steeper climbs. These are quickly rewarded with nice elevated trails that look out over the valley and the mountains across. Roughly halfway, you will come by the Lac Vivier fishing lake right across from the hamlet of Bionnay.  There are some picnic benches there which make for a good halfway rest point.   There is even a barbeque pit. From there you will pass by the hamlets of Le Quy and Les Hoches before finally arriving at Les Contamintes-Montjoie. Once there you can visit the Eglise de la Sainte-Trinite church and have a meal or a drink at one of the many bistros and restaurants in Les Contamines. All in all, a nice valley trail which is both children and dog friendly. 

The D902 main road which runs through the entire valley is never very far from the trail and there are multiple bus stops along this road which will enable you to shorten the trail at will. This bus is also our recommended way of getting back to your starting point. The trail can be done in the oppossite direction of course which will mean significantly less vertical gain but the views will be less nice in our opinion. Lastly, you will be happy to know that the UTMB 170 kilometer trail race follows this trail as part of the race.