Hi Jan,
Many thanks for your helpful reply.
Indeed I had a problem with my verticals on this pic (Sdwhitton earlier posted "your target should be at the same height as your camera height")
This is very helpful as I don't know the "rules" for archviz...
So I hope that little by little I'll get there !

When you say "wide lens" does this mean going to my FoV setting and lowering it ?
For my latest indoor work (see "white kitchen and bottles" topic) I lowered it and I was much happier with the result, as a setting of 30-35 tends to greatly lessen geometric deformation.
I also put my camera at around 1.60 meter from the ground in exterior scenes now, this way it is set up at the same level as the human eye.