Hello Olivier,
I just listened to "Soleil De Paris" and consider it to be a very nice and well made ballad. All instruments are clear and distinct. I was very impressed with the soundscape of the acoustic and electric guitars as well as the electric bass. I like the way you left the electric guitar in the mix after the first solo. By the way, you did not mention if that was you, or someone else, singing the vocal but it is a pleasent voice that sits well in the mix.
Some suggestions:
Snare drum brushes sounded nice but the tom hits and ride cymbal were not as pronounced. I would pan the ride cymbal more to the right of center. I would also boost higher frequencies on tom and ride cymbal. Alternately, ask drummer to retrack tom hits and ride cymbal using stick instead of brush then mix the two sounds together.
There is very little lateral blending of the channels. You have three lateral spaces: left, center and right. At the same time, your use of effects is very effective as you build a very nice sounding soundscape. You may want to consider using effects to help blend the lateral space into a whole by panning the the instrument and the effect opposite each other. For instance if you have the acoustic guitar panned 30% left then pan either the guitar delay, reverb or both 30% right.