Designed before 1965
Blazon: Gules a pale wavy argent surmounted by five castles triple-towered in saltire or
Yep, another Robert Louis! Which also makes me think these arms probably aren’t official. Unlike many other of Louis’ designs, this one does violate the law of tincture by placing one of the castles or on the pale argent; this could have been avoided by counterchanging, or making the center castle a different color. I don’t have a good idea of what the castles are supposed to represent, so I don’t know if there’s a reason for not doing that. It’s possible, maybe even probable, that the pale wavy is supposed to stand for the river Vienne which gives the department its name.