I have been researching about Gendarmes or man at arms but i cant seem to find out what type of helmet they may have worn all i know is that they wore full suits of plated armor and are usually from France during the Hundred Years War and here is my guess the close helmet?? if someone could tell me if all of europe had gendarmes in their medieval armies thanks and one last thing did Germany ever wear the close helm or armet i know they rather chose the sallet which evolved into the helmet that germany wore in both world wars

There have been previous discussions about gendarmes. The search function should help you. :)

The true close helm dates from after the Hundred Years War. The term "gendarmes" (perhaps gen d'armes) pretty much just means man-at-arms. So while the term is French, most countries had some kind of equivalent term and person.