An equivalent English blazon might be:
Azure, two mullets of six points and one mullet of eight points Or, two and one, a base Or charged with a cross patty Azure.
I have attached a scan of this coat of arms from Rolland and Rolland's Illustrations to the Armorial-Général.
The "casque coronné" (crowned helmet) simply describes the helm which would sit atop the shield.
I hope that all of this is helpful to you.