found it
do you need to pay any taxes or customs?
Yes, they calculate it at the checkout so you pay it in advance. The parcel should go through customs without any further fees.
However, I read elsewhere (don't know whether here or in a German forum) that you might get a call from customs (you have to add a phone number and it is advisable to do so, because this is shipped by DHL Express, not regular DHL) about the parcel and they will ask you to send a receipt. Usually this is handled by DHL customs office in Leipzig (regardless of the destination city). Sephora does add a receipt outside of the parcel for them to read but they will ask you possibly anyways. I always mailed then my receipt again where the taxes and duties are listed and said that it's already paid on checkout. There is also somewhere a sentence on sephora site that says so, so then I'll add the link.
Usually then the parcel is cleared and will be delivered soon after that.
Edit: You do not have to pay "customs fee" [Zoll] up until the value of 150€ (including shipping) but even then you have to pay something call "Einfuhrumsatzsteuer", something like import tax.
Your friend could check on the website of German customs, too, just to be safe.