Due to economic necessity, the lace workers moved to France, as their craft was more appreciated there, allowing them to make a living. They took with them their toy bulldogs, as they were well suited to small, cramped living quarters. Being crossbred with terriers, they were also excellent ratters, a big problem in those days. Even today, Frenchies still have a very strong hunting drive where vermin are concerned.
The French fell so in love with this small bulldog that they imported just about every one left in England. The French adored the "Petite Boule" as they called them, and they became the star of the Parisian working class. As they became more popular, they came to the attention of the rich, and it soon became a status symbol to own one.
American tourists discovered the Frenchie breed and began to bring the dogs home with them. Interestingly, Americans are the ones that bred for the bat ear, as there were previously two types: a rose-eared type (like English Bulldogs) and the bat-ear. The bat-ear was favored and became the standard. This is what gives these dogs the distinctive look they have today.