Hey Thibault

Nice render.

I like the central, single vanishing point perspective and straight verticals. Yeah, architectural renderings are generally marketing driven, everyone want to see blue skies and nicely lit rooms. I like the colour/material palette.

The picky architect inside me has some comments:

1.- The way the stair stringer meets the floor above looks wrong. Lower the ceiling so that it aligns with the lower edge of the stringer. if that makes sense.
2.- The way the balustrade uprights meet the timber handrail is odd.
3.- There seems not be a fridge or a hood over the hob. Theses people only eat take aways !!!. There is no oven either....
4.- I can't figure out what's the white box over the (window, door?) on the right hand side. It's not pretty. Much better would be to see the whole of black frame.
5.- The exterior blinds on the window seem to be floating, there is no frame or fixings. They seem not to have a thickness, but might be the angle.
6.- The leaves on the right hand (whatever species it is) seems to be there with the sole purpose of hiding the exterior. It would be much nicer to see what's in the horizon, a city, a neighbour building the landscape, whatever it is. The sky looks plain blue. Needs perhaps a good photo of a sky. Perhaps the glimpse of a cloud.
7.- The long curvy planters I find odd, but this is subjective. The black one on the balcony bothers me more than the white one.
8.- From the point of view of composition the stair doesn't bother me. From the point of view of design it does. You are wasting about 4 square meters of the that living room by having a corridor behind the stair. Can't the stair be pushed towards the wall?. I can see there are sliding doors behind and and a balcony above. May be the design is not the point of this image. I agree with the odd arrangement of furniture under the stair.
9.- the classic looking door on the first floor bothers me in this supper slick modern flat. The handle even more !. The door seems to be missing the frame.
10.- The left timber handrail is clashing with the wall. and the inclined bars and uprights terminating against the ceiling. Move that stair !.
11.- There should be a couple of sockets over the kitchen top, to plug the toaster and the rice steamer.
12.- On the top corner of the window, there is something odd with the wall, the lintel avobe the window seems not to have thickness, like a thin sheet hanging. It this a pelmet?.

Non architectural comments:

- The book on the side tables seems not to be textured. Nor the glass next to it. Nor the books on the tv stand.
- I really like the innox steel material on the legs of the side table but not so the one on the sink tab and sink. They look white.
- I really like the grain of the white wall in the light.
- The back cushions in the sofa look to straight. Cushions and pillows are really hard to get right. I say this without ever modelling a convincing pillow myself, let alone a sofa. whats the white scribble in the very forefront of the sofa?. Are the legs of the sofa meant to be metal?.
- I like the timber floor and the satin looking metal of the stair. are the steps timber, they look a bit metals to me?.