I could hear "Repose !" (which I guess means "At ease!") but not the other ones.

At a ceremony, I heard the French officer yelled something that sounds like "homme", at which the soldiers would stand up straight and do something with the guns with a sharp motion. All went very quick. I wonder what that order was.

I would appreciate it if someone could help solve the puzzle. I have no problem hearing longer French military orders, such as those given in a hostage rescue situation:
"Les mains sur la tête !"
"Nous sommes français !"
"Tout le monde par terre !"
"Sortez du cockpit !"

"Repos !" (without the "e") = "at ease !"

Each movement has a specific command : what was exactly the sharp movement ? Can you provide a video/audio link ? Was it during the ceremony to honor the French soldiers who died in Afghanistan ?

Yes. It was that ceremony.

The movement was very quick - they stood up and their hands must have touched the gun because I heard the sound of it. When they finished the act, their hands were not on the guns. The guns were just hanging on their chests.

I am now thinking the officer might be yelling "L'avant !"

Or "Present !"

The only commands that I think of are :
"Presentez arme !"
"Reposez arme !"
"L'arme a la bretelle !"
"L'arme au pied !"
"L'arme en bandouillere !"

I will look at the ceremony.....

http://www.youtube.com/watch?v=RArxOb6ixBw

Do you hear this command on this video ?

"Fermez le banc !" (9'25'') ??
"Aux Morts !" (10'51'') ??

Yes, yes, thank you so much.

"Reposez arme !"
"Presentez arme !"

Also "Presentez arme !" at 6:02 ("Ouvrez le banc !")

Could you explain "ouvrez le banc" and "fermez le banc" ?

I really love hearing La Marseillaise ! It moves me every time...

In this situation, "le banc" is the part of the ceremony when the President give the medals (decorates ?) to the soldiers who died for the country.

Thanks a lot. I watched the ceremony live last night on a different channel. I am glad to be able to see it again on this video of France 2.