Our experience has generally been very good, especially when our Frenchies have been introduced to other pets when they were still relatively young (12 weeks or less). We have not had any problems introducing any of our puppies to other pets, including cats when we had them. Frenchie puppies are so friendly and loving they just don’t seem to have a problem with anyone or anything, and our adult French Bulldogs have not had any problems what-so-ever in accepting a new puppy in the group. In no time at all, they are great buddies and it looks like they’ve been together forever.
The only problem we’ve ever had is when we have introduced new adult females to each other. Sometimes this goes well, but we have had occasion when adult females have not accepted each other and we have had to keep them separated. This is especially true when one of them is in heat or expecting. When all of the group is spayed or neutered, there is very little chance of conflict.
If you adopt a French Bulldog puppy, the chances that you will have any problem introducing him or her to another pet, especially another dog, is very small.
If you are looking for an adult Frenchie which will be the only pet in the home, you will have no problem at all. However, if you already have a dog or cat, problems are possible, especially if they are not introduced correctly. You can use a play pen or kennel to introduce them (one on each side of the barrier) and observe their response. If they seem to accept each other, you can introduce them on leashes. If they continue to accept each other, you can put them together under close supervision until you are sure they will get along without you being there.