There are many products available that claim to reduce pet anxiety.

Some may or may not work for your Frenchie; every dog is different so you’ll have to try them to see if they work for you.

I like the ThunderShirt for my dogs that are scared of loud noises like thunderstorms or fireworks. It’s also good if your Frenchie is just a generally anxious dog for whatever reason.
I also like Zesty Paws Hemp Elements treats when I feel like my Frenchie needs something to just slightly take the edge off without completely sedating them (with something like Benadryl which completely knocks them out). These are good to relax your Frenchie without the negative side effects traditionally known for sedating your dog like worsening their breathing problems… so for this reason, this is something that I would give my Frenchie before traveling on a plane.
I like the Happy Hoodie for the same reasons as the ThunderShirt— it’s nice to protect your Frenchie from any loud noises without having to put on a huge coat. It’s also nice to use when grooming them.

Give them a comfortable space— make sure your Frenchie has a comfortable place to rest and relax, such as a cozy bed or crate. This can help them feel secure and reduce anxiety.
Minimize stressors— identify any stressors in your Frenchie’s environment and try to minimize them. For example, if loud noises like thunder or fireworks stress out your Frenchie, consider playing soothing music or using a white noise machine.
Provide regular exercise— Frenchies need regular exercise to burn off excess energy and stay healthy. A daily walk or playtime in the backyard can help keep your Frenchie calm and happy.
Establish a routine— dogs thrive on routine, and having a set schedule for feeding, exercise, and playtime can help your Frenchie feel more secure and relaxed.
Practice positive reinforcement training— positive reinforcement training can help build your Frenchie’s confidence and reduce anxiety. Reward good behavior with treats or praise, and avoid punishment or negative reinforcement.