Here we have signage with he regional reglement for parc operated by environnement.brussels. 

General rules is that dogs should be leashed except some zone. 

The signage scheme : https://environnement.brussels/media/12327/download?inline

It's quite unusual that dog is forbiden on "promenade verte". 

Don't find any interdicition here on the official atlas : https://geodata.environnement.brussels/client/view/a8af35c3-f0c6-45c9-8615-3dad4988611f?_ga=2.139075763.1827622902.1657619462-1908285317.1657619462

Also not on the "on construction" website : https://gardens.brussels/fr/espaces-verts/val-dor 

Last imagery : https://www.mapillary.com/app/?pKey=506223538267142 don't show any interdiction here. 

Survey/research needed because suspicious changeset : https://www.openstreetmap.org/changeset/142649600

