Pierre this is much better. Im glad that you didnt give up. You have a lot of talent. Everyone gets frustrated at some point. I hit dead ends all the time, but there is always good advice here to bring an image up to the next level.
This last image is much better. There is more contrast in the image, and objects look grounded and not floating like in the last few that were too evenly lit. This is a problem with only HDRI enviornments and sky dome unfortunately. Is this last one only emitters? Which probably took way longer I bet. The only thing that does not look right to me here is the window area. I would try adding glare so that you get some glow from the flat white window. I found glare to be too slow and buggy right now so a quick thing to do is use photoshop gaussian blur to a white rectangle on a seprate layer around the window then mess with the opacity of the layer to knock it down a bit. I also bunred the edges of your scene to bring the focus to the center of the image more. Hope you don't mind. The other option is to add an enviornment outside, but this will take away from what you are trying to show which is the bathroom itself. I prefer just to add some glow in situations like this. Hope you dont mind me tweaking your image.
One quick thing that hard edge of light reflecting from the cieling is distracting on the marble to the right of the bathtub. Is there something that can be done with the emitter so you dont get that. Maybe put in an mxi emitter up at the cieling where the light falls of at the edges of the mxi. Its not that big a deal though.

Industrial Designer
Concept Center International
www.ericlagman.com