Route: Tour of Annecy Lake (Voie Verte) (France)

I suggest this FKT Route because:

1. It's geographically and landscape-wise relevant

It starts and finishes in Annecy, nicknamed the "Pearl of the French Alps". The path is around the blue water of Annecy's lake and it is sorrounded by the highest and most spectacular mountains in Europe.

The path itself is one of the most famous and ancient cycle route ("voie verte") in France. Being a cycling route, the route is pleasent and the car traffic is not a problem

Please, find further information on the website of the Annecy's Tourism Office: https://www.lac-annecy.com/immanquables/la-voie-verte-du-lac-d-annecy/

2. It's Technically Interesting 

The distance is long enough to be challenging, but most of runners can deal with this kind of a marathon distance.

3. There a NOT Races on this path

Note that there is an marathon race called "Marathon Annecy Lake", but the percours doesn't sorround the lake: it is only on 1 coast "back and forth" (for more details, see the folllowing website: https://event.ahsa-athletisme.com/language/en/races-en/annecy-lake-marathon/).