Hi everybody !
As a french woman, I will say that you have to ask the bride if she wants hat or not !
She must have a very clear idea of what she wants ! Sometimes you have to wear 2 "tenues" = one for the chirch, one for the dinner ! For the chirch, you will wear a hat, and for the dinner a long dress.....BUT only if it is a BIG wedding !!!
Ask the bride if she wants this kind of wedding !

She is THE ONE who decide !
HAve fun !