If you needed concept art for 16th century Gendarme you can find nice one here:

http://www.stratcommandcenter.com/fo...howtopic=11788

For 15th century is the one from last post ideal. Its very hard to say if they mostly wore sallets ot armets in late 100yrs war and several decades later.

Are you planning one general model of Gendarmes or two different?
If only one they should have armets or close helmets these were more common if speaking about mid 15th- 16th century.