I confirm that there is indeed no plaque indicating the nomination "Esplanade Jacques Brel" of this place once on site. I added the name based on the map that is aksi published on the website of the municipality of Schaerbeek: https://issuu.com/1030be/docs/brochure_parc_josaphat?e=23589250/53371522
On this pdf it's not legible, but on the printed version you can clearly read "Esplanade Jacques Brel".
However, I don't know anybody who knows or uses this nomination, so I am I'm inclined to remove the name ...