[germanier]

The first letter you got after a birth in Germany used to read something like this and is addressed to the newborn (hopefully they have changed it by now):

Regarding: Assignment of the Tax ID according to § 139b of the tax code

Dear <name of the newborn>,

the Federal Central Tax Office has assigned you the Tax ID <number>. It is used for taxation purposes and valid your whole life. Please keep this letter even if you are currently not paying any taxes. Always mention your Tax ID when communicating with financial authorities. Please also note the information on the back.

Kind regards, your Federal Central Tax Office