Looking at a possible flight to Germany for some shopping I started thinking about clearing customs when you have goods to declare (and also need them officially exported from Germany to get back the VAT). Who could do that e.g. at Donaueschingen EDTD?
Well perhaps look at their website or AIP.
Customs Regulations:
Flights abroad during working hours, (0771) 2585 For non-commercial and commercial occasional transport without commercial goods. For trips and trips from / to third countries (not EU) PPR MNM 2 HR at OPS.
Flights abroad during hours (0771) 2585. For non-commercial traffic without merchandise. For non-EU countries PPR MNM 2 HR from OPS
If I remember correctly, German customs agents may be requested to come to any airfield, but there is a fee for that.
No fee.