A priest's vestment is simply known as a gown or robe.
robe
Vestment
une robe
During Baptism the color of priest vestment is WHITE.
gown
robe
une robe (fem.)
a cocktail gown is 'une robe de cocktail' in French
A dressing gown / bath robe
A wedding gown is 'une robe de mariée' in French.
It's "Robe de Bal".