It took us roughly 4 months to housebreak our French Bulldog, Pepper.
We didn't crate train Pepper. We just put up kid gates and kept here in the kitchen with a puppy pad down when we were gone. When we returned if she went on the pad, she was praised, but then taken outside for a romp around the backyard. The pads were only put down right before we left and when we came home they were removed.
I grew up with Miniature Schnauzers. Pepper is the first non Schnauzer breed I've ever owned and when they say French Bulldogs are harder to housebreak they are not kidding.
Peppers an extremely smart dog but also extremely stubborn. But every dog within a breed is different. I found that Pepper responded to different tones in my voice and a reward system. If she did something good, I used a happy playful voice and rewarded her with a few minutes of playing. If she did something un-wanted, I'd use a deeper serious voice to correct her and put her in her bed.
As I said, every dog within a breed is different so what works on one may not work on another as far as training goes. But it did work on my Frenchy