All officers, right down to platoon commanders, were French (ie white); in very rare instances, a major act of bravery could be rewarded with a commission (I'm only aware of one, but there may have been more). All NCOs were native (ie black). Most support weapons were integral, as per metropolitan French infantry units (not sure about the smaller anti-tank guns, though), so again, crews would be black.
Note that, in action, all ranks wore the helmet pretty much without exception (as per any number of contemporary photographs), rather than the fez. I'm currently building a Sengalese platoon myself, and have purchased the Crusader infantry/supports range. That said, I've also purchased a section of the Warlord fez-wearing guys as NCOs/squad leaders, and the two coup-coup (machete) waving guys as markers to denote the bonus the Senegalese receive in fisticuffs.
Hope that helps.
BvW