Contrary to popular opinion, teaching your "Frenchy" to use a crate is far from cruel. In fact, when you give your pup a crate, you are giving him a private place that's all his own. In turn, this will give him a sense of security. More importantly, French Bulldogs love to have a "den" to hide away in and cuddle with a nice blanket or bed.
At the same time, crate training your Frenchy so that he will stay in it while you are not available to supervise him is a great way to protect your pup--and your home--from injury. You can also use crate training as part of your overall potty training process, as most dogs will not eliminate where they sleep. They prefer to have a clean "den" and will learn to hold it for longer periods of time to ensure they don't make a mess in their home.
French Bulldogs are both curious and highly intelligent by nature. You can use these traits to your advantage at the outset of training by encouraging your pup to explore his crate by using toys, treats, a soft bed, or a fluffed-up blanket to "lure" him in. The main intent of this training is to take your pup's natural instinct to find a den and put it to good use by training him to see the crate as his "den", which, in turn, will ensure he wants to spend time in it.
You can start teaching your pup to use his crate from the day you bring him home. At the same time, you can teach the same behavior to an older dog. The only real difference is that it might take you a little longer to teach an older dog to accept the crate as his den.
Start by shopping for the right crate, one that will fit your pup once he is fully grown. Since Frenchies are not considered to be a "large" breed of dog, you can get away with buying only one crate. It should be big enough for your dog to move around in comfortably once he is fully grown. You will also need a few items to furnish it comfortably for your pup.
The furnishings should include a pad or wall-to-wall carpeting, a comfy bed, some really fun toys, and a blanket. You don't have to go overboard, but you need to make sure he is going to be comfortable and enjoys spending time in his "den." Oh, and you will need a plentiful supply of his favorite smelly treats.