You need to go to Bullingen to see resident D reg. I know the Belgian permit was aimed at resident French registered aircraft, but it has the effect of drastically reducing visits by foreign permit aircraft, because it is expensive and bureaucratic. A visit without a permit would be illegal and invalidate insurance, which is a risk not many would take. A great shame, because Belgium offers some very good destinations, many of which I enjoyed flying into when I had a G reg permit aircraft based in Luxembourg.
BTW, the UK is the only other country that charges for visits by permit aircraft, although homebuilts and those registered in France are exempted.