Hi Abdel, thanks for sharing. However, this community is a very global one and not all our users speak French. Can you add a description to your post so users will know upfront to expect before opening the PDF? Thanks!
Je ai lu un peu français. Mais pas bien ...
I think the problem you are asking is in your final screenshot. It seems you want the surface to be tangent along the internal boundary illustrated... but it is not. The topology of the internal skeleton of curves forms a "T". This can be challenging when working with surfaces. Here are some things to investigate.
This surfacing problem is challenging with traditional parametric surfacing features because of the internal skeleton. In my experience, the easiest way to do this with the standard/traditional parametric surface features is to use ribbon surfaces. If you have the ability to, you should also look at ISDX Style features. They can help with more complex surfacing situations like this one. Or even better, look at the new "FreeStyle" surfacing features that were introduced in Creo. FreeStyle surfacing is calculated using subdivisional modeling. You don't have the think about the internal skeleton of curves and the required tangency and curvature constraints before building the surface. FreeStyle surfaces are very powerful and the resulting suface quilt is quite good and doesn't require you to plan what the quilt structure looks like for complex surfaces.