There is often a gift tax.
The reason for this tax is often that there is also an inheritance tax.
This tax comes probably from the idea that all people should have equal material wealth in life.
So, if you get a gift, there should be a tax on it.
In some countries the tax has been as high as 80 percent of the value of the gift.
You can find out more about this matter on the international law forum in the following countries: