[thegp]

Piggybacking your comment:

In Germany, the legislative has created a way to handle this:

If you are a recognised nonprofit ("gemeinnützige Organisation ") you can give your donors donation receipts which count for tax purposes. It is literally an invoice for a donation, but importantly the transaction will not be taxed, the donors simply deduct it from their income and the recipients simply have more money, without accounting overhead.

If you are a nonprofit which works with international companies (we for example worked with them to organise events for students), this can be quite tricky to explain, since the concept seems a bit alien to their accountants, who are used to sponsorship deals or simple licences like op described