Yes, you can donate assets directly to your grandchildren. They will then have to pay succession duties. However, do bear in mind that minors cannot accept donations by themselves due to their legal incapacity. Your notary will be able to explain the possibilities of addressing such incapacity.

By including your grandchildren in your estate planning, your inheritance will be spread over a larger number of heirs, which will decrease the overall burden of succession duties. Furthermore, you will save your grandchildren from having to pay succession duties again when their parents die. Grandparents can retain certain rights over donated assets, such as reserving a usufruct.