College Jean 23 is good but not known as the highest academically in the area. The most sought after academically are St Michel, Sacré-Coeur de Lindhout, Dames de Marie, Jean Absil, College Don Bosco, Mater Dei. The secondary schools admissions procedures have changed significantly 3 times in 4 years, in the last 2 years, based on priority (siblings or "adosssée" primaire) and then on geography between home, primaire and secondaire. IF this system stays for the next 10 years and is relevant for your child, your child will get priority for Jean 23 into secondaire from either of the Jean 23 primaires, if another secondaire is chosen, you will get more points if your child goes to the nearest primaire, the primaire is nearest to your secondaire.
But I think it is too early to choose a maternelle based on the future in 10 years. If Jean 23 is on your way to work and you like it and think it's the best school you've seen, then just go for it. Change primaire later, if necessary to optimise secondaire.
Jean 23 Parmentier is a fondamentale, there is no separate primaire, with just 12 classes, I would expect everyone knows everyone there.
It might be worth asking the head the breakdown of which secondaires last years and this years 6e primaire students chose, if you wish to know how academically high the primaire classes are.