Thanks to you all, gentlemen! I'm !
Some other important details: the floor coverings; I have them drawn with SKETCHUP textures and fitted to the right dimensions of the floors, then printed on self adhesive paper. On these drawings, some parts remains in white color: it's the exact place for the partitions; by this way I avoid me to take measurements on a blue color to put them in place! easier for me and less tiring for my eyes!!!
Upper level:
Lower level:
It's not very large, but I hope you can enlarge these drawings.
It remains to stick them on the floors and add some partitions: the work for tomorrow!
jpv in France