Donations with out consideration, i.e. presents, are usually topic to reward tax until exemptions apply. The private allowances between dad and mom and kids are fairly excessive at 400,000 euros. But there are pitfalls lurking there too. The private allowance is just granted each ten years; purchases should be added up over a interval of ten years.
https://www.faz.net/aktuell/finanzen/meine-finanzen/freibetraege-bei-schenkungen-vorsicht-bei-groesseren-geschenken-110069136.html