Ok ... Thanks for your help. Do you mind someone in particular ?

I found this topic https://bbs.archlinux.org/viewtopic.php?id=138427 into which someone has the same problem than me but the TERM=xterm-256color in Konsole's settings did work for him, it didn't for me . I wonder why ...

I am sorry for the double post, but I have finally found the solution . It was very simple. I am almost disappointed according the spent time... A pitty that I didn't think to it before...
I have just put background=light into my .vimrc file and, strangely it's worked.

Thanks for your help and see you soon !

changing background worked for me too. Strangely as background is not close to light.

Just for the reference, nvim supports 24 bit color themes, and it works on Konsole: