Floor plan design single-family house (city villa 140 sqm) on a slope with double garage

Maybe you can still use the soil for the garden part as ground leveling. I wouldn't build on it – I mean on the soil.

You mean 2 full floors! That's not just a city villa. For me, a city villa is classically square and with a hipped roof. We are building 8.25m x 11m, so 139 sqm with a basement because of the slope (3m down to the garden over 22m length).

As many have already mentioned, including myself. Go to a general contractor and have them tailor an offer with a floor plan where all ground works up to depositing and/or filling are included. You can't do more than that, and no one can tell you if it will then be 300 or 350k€. Post the general contractor's offer here and we will check if it is okay. Then you will also get an objective feedback on your floor plan.