Wie heißt diese typische Mailbox-Schriftart?

That is a variant of the DIN 1451 I think! It’s used a lot on stuff like this all around Europe:

https://en.m.wikipedia.org/wiki/DIN_1451

You can kind of see some clear similarities in the structure of the a in this image – even if a bit more elongated in the name ‘Paolo’.

https://en.m.wikipedia.org/wiki/DIN_1451#/media/File%3ADIN_Mittelschrift_Beispiel.jpg

You can use the What The Font tool:

[https://www.myfonts.com/pages/whatthefont](https://www.myfonts.com/pages/whatthefont)

Looks like „[Steinschrift](https://ibb.co/h24JJHy)“ first font I‘ve learnt 35 years ago. Ignore the colour, was trying out new gel pens