https://www.openstreetmap.org/relation/14615065

The outline for the architect data and wikipedia is not correct and should be only a building part.

https://monument.heritage.brussels/fr/buildings/30617

« Comprend quatre ailes autour d’une cour centrale » : on latest aerial it’s hard to have the outline with this description as the building is being renovated but if we take the https://bruciel.brussels/ 1953 or in Josm Urbis aerial 2009 we can clearly show the central courtyard.

(…) trois fois onze travées sous toit mansardé (…) :

- From Place du Trône : 
https://www.mapillary.com/app/?pKey=1053406922301774
- From Rue de la Pépinière : 
https://www.mapillary.com/app/?pKey=264682252459153 (not show all 11 but as the bay is repeated on the level 1 you can count easyly : https://www.mapillary.com/app/?pKey=589418919849137 ) 
- From Régent : 
https://www.mapillary.com/app/?pKey=1379480072640447

For the record , wikipedia article (CC BY-SA 3.0 ) in nl has correct address and fr version is wrong ... behind the licence concern , we have plently exemple of that kind of error and copy paste such data in osm without verification or research is clearly problematic. 