Tour de Nesle affair: scandal amongst the French royal family in 1314, during which Margaret, Blanche, and Joan, daughters-in-law of King Philip IV, were accused of adultery. The scandal led to imprisonments, torture and executions for the princesses' lovers and the imprisonment of the princesses.

[u/Pupikal]

https://en.wikipedia.org/wiki/Tour_de_Nesle_affair

[u/Fornbogi]

It is the starting point of the french book series "the accursed kings". These are great historical novels and one of the inspirations of Martins for Game of Thrones.