EUREKA!
I don't know if it's a translation error, I can't read anymore or simply a huge misunderstanding...
In the " Entities to import " category, I understand " what comes from the WWTP I import ", 
there is a " User-defined attributes / Custom properties" box. I'll let you guess the rest...
If checked: ALL MY properties are present, nothing to do with " Entities to import " of the WWTP 
Frankly, do you understand/interpret how this box in this category?
It's me walking next to my pumps or...
A big thank you to all for the time spent on my problem.
It's not the first time SW has done something like this to me: an ultra-simple problem that makes us look for twisted solutions...
I think it's part of his DNA 
After 12 years of use, it still knows how to surprise me...
Haha, THE box that made me wonder about the identical parameters between STEP and parasolid xd
Obviously, it's for integrated parameters calculated by equation or not
As you say, the mysteries of Solidworks!!
And I was already having trouble (when I started, it's better now...) with the " Delete " notion of Solidworks.
When you think that Dassault is a Frenchie company at its core...
I wonder if the " translations " are sometimes so approximate in CATIA...
Speaking of translation... There's one that came with SW2024 that I love.
Do you know all the Bounding boxes? These prismatic capable volumes? SW2024 introduced the " cylindrical bounding box " which they of course translated as... cylindrical viewing cube !!
I love it.
A cube-shaped cylinder ... This is revolutionary in the world of design!! It opens up prospects 
