Thank you for the time you will devote to me, and especially sorry for my approximate English.
I made a “gotocenter” script.
It works but it is unfortunately not what I want, I explain:
Here is the starting point for my curves.
Here is the result of my script
Here is what I would like to get.
For information of grouping or not the curves do not change anything.
But I don’t want to go in this direction.
Thanks a lot for your answers.