American breeders decided early on that bat ears should be considered the standard, because they are more distinctive.
Since then, rose ears on a French bulldog have been a disqualifying characteristic according to the American Kennel Club’s breed standard.
A French bulldog can’t weigh more than 28 pounds. Well, it can, but exceeding 28 pounds is an automatic disqualification for a show dog according to the AKC’s breed standard.