The first part of the GR 121 trail Wavre - Côte d'Opale is documented in the topoguide GR 12 Wallonia, a french edition of the Walloon SGR organisation. It was published in 2009, so it's still quite recent.

 

The topoguide describes the trail over a distance of 62 km., starting in Wavre. It ends near the Bois de la Houssière situated between Braine-le-Compte and Henripont, that's where the GR 121 and GR 12 trails split up.

 

The map below shows the hikes we've already done on this trail (red line). The orange line represents what remains to be done on this part of the trail.

Below the map you'll find the links to the individual hikes on this website.