bxl-forever
Somehow, yes.  They served as a local tax (or customs) office centuries ago, but I am afraid there will never be a proper tag for buildings that were dismantled and rebuilt elsewhere, moreover to become something else.  (Apparently, it even served as a police station some decades ago.)

I suggest to do something like:
name="Anciens pavillons d’octroi - Voormalige tolhuisjes" + FR/NL
url=https://monument.heritage.brussels/nl/buildings/16053
description=* (find something if you want to explain)
heritage=*
+ maybe something related to what those building are currently used for (museum?)