It's ok i have restore my website after your customization. So no changes on my part.
It comes back to the starting point, in
Settings - Single Category Settings - Single Category Layout - List
and Categories - Sale (old/new) etc ... - Single Category Layout - List
but in frontend, the layout is always Default. essaisitemag.hebergratuit.net/joomla_age...9-Old/Old?Itemid=140
And if I can not customize the layout, as I had done on the free version, I still prefer the layout "list" and not the layout "default".
Thanks for your help.