Riolo says ASSE sold the defender for the right price.
He told But Football Club: "It's like that. You felt that at €30m, it was no, but at 40, it would be yes.
"There is always a number that makes it necessary. It's the life of a club. Today, clubs live off player sales and TV rights. And we see the uncertainties there are with broadcasters.
"Besides, Fofana wanted to leave. 'Sainté' could not offer him to play the Top 5. He knew he was there to be sold, in 2020, in 21 or in 22. He had this opportunity with Leicester, he did not want to let it go.
"It's our football that's like that. Players are commodities, in a Ligue 1 which has become a training center for the major European leagues."