Land & construction

Land and buildings are not equal when it comes to depreciation!
You deduct these investments in proportion to the business use you make of them. For buildings, you should also take into account their depreciation rate: for a useful life of 30 years (estimated), the indicative depreciation rate would be 3% per year.

Certain categories of investments are eligible for the investment deduction, both for self-employed as a natural person and for self-employed persons in companies. The FPS Finance website lists these investments, see if your investment is included: https://bit.ly/2KJaNwc.