Forget what I just said, I just re-checked and put the "solid" behavior to the wrong object. Thank you very much for your help, I will be able to advance in the development of my game.
For the people who came on this topic to solve the same problem as me, you just have to do as on the screen below.
S_Entrée_01 = The object that will allow you to go from one layout to another.
"ruins_meet_flowey" = The next layout.
It will also put the behavior "solid" on the object (for me it's for "S_Entrée_01).
You have to put the behavior "presist" on the player sprite too.
I create a S_Entrée_n ° for each entry or exit. You, do it as you feel.