Bayern Munich decision not to extend Tolisso contract is the right thing in my opinion, because Tolisso has often been injured so he has not been able to make a big contribution to Bayern Munich, I don't know the reason for OL decision to sign him again, because even though he is still young but his performance so far every season has continued to decline, especially since Corentin Tolisso injury history will be hampered his later performance with OL.
Maybe they think they will be able to sell Tolisso again in the future, as they did when they sold Tolisso to Bayern Munich. And actually, Tolisso's age is still relatively young for a footballer. If he shines again while playing with Lyon, it is not impossible that Lyon will benefit again when there are clubs who want to buy him. In addition, Lyon also got Tolisso for free.