Are parents allowed to build a house on their child's property?

How fixed is the parents' plan to build and what is supposed to be built? To me, the simplest solution seems to be that the parents build and then gift the house - possibly in parts.

For tax reasons, parents would like to gift their child a plot of land. However, they might want to build a house on this plot in the future.

Maybe just add a bit more information to the question. What exactly is intended? What values are involved? What time frame? Why build a house? Single-family home or residential complex? Owner-occupied or rental? Etc.

Maybe just bring a bit more substance to the question. What exactly is to be achieved? What values are involved? What time frame? Why build a house? Single-family home or residential complex? Owner-occupancy or rental? Etc.

Notary and tax advisor will be involved, this is just to get an initial overview.

Parents purchased a plot of land in 2014 to possibly build a country house/weekend house someday.
According to the standard land value, the plot is worth 100k, market value about 200k.
Maybe the parents won’t build but instead acquire another property with land.
Instead of selling the plot for 200k and gifting the amount to the child, one could gift the plot at the gift value of 100k and save gift tax.

Instead of selling the property for 200k and gifting the amount to the child, one could gift the property with a gift value of 100k and save gift tax.

Do you have a problem with the tax exemptions? They are 400k within 10 years. Apart from that, the tax office conducts a valuation. This can also result in 200k, so that you gain nothing.

Do you have a problem with the exemptions? They amount to €400,000 in 10 years. Apart from that, the tax office carries out a valuation. This can also result in €200,000, so that there is no gain.

Exemptions would be something to save. I was told that if the land is undeveloped, then §§ 178,179 BewG apply. So standard land value * area

And the assessment by the tax office can often be too high. Therefore, always consult an independent expert whom you pay.