Lac des Truites is a lake in Haut-Rhin, France. At an elevation of 1061 m, its surface area is 0.028 km². The name is a mistranslation of the German name Forlenweier. Frenchifying the toponyms of Alsace, the French authorities misread Forle as diminutive of Forelle (truite, trout) when in fact it is a diminutive of Föhre (pin, pine). The lake has various names, and on maps can be seen as 'Lac des Truites", 'Lac du Forlet', or 'Lac Vert'. On its borders is a Ferme-auberge (Ferme-Auberge du Lac du Forlet) which is quite popular, especially when the weather is nice and warm.