Well I don't think one should focus too much about white armour as such. IIRC brigandine armour was good enough to stop light crossbows and arrows, at least in early 15th century. The actual quality and level of armour might not be easy to say but AFAIK Italian armourers were spitting out lots of plate for export so it cannot have been that rare among the men-at-arms. The war horse generally cost more than standard armour anyway so if a man-at-arm could afford a horse then one should expect reasonable armour too.

Wealthy towns like the Flemish towns produced some well protected militia AFAIK. My guess would be that towns like Paris, which did end up with large forces of militia, also had well protected soldiers.

http://www.deremilitari.org/resource...s/bennett2.htm for an article on tactics in the HYW.

If we look at the French force at Agincourt then (based on Anne Curry) something like 2/3 were men-at-arms and the rest mainly missile armed infantry with a majority of these being archers.

Burgundian armies seems to have gone more the "English way" with lots of missile power and near the end of the HYW the French were doing the same thing with their compagnies d'ordonnance supported by Francs-Archers.

In the early part of the HYW the French were also pretty top heavy in their make up but having mercs handling the missile part. And of course occasionally using their low quality militia levy. Numbers would vary so would have to look it up for specific numbers, if there are any proper numbers for the militia at all.