I repeat This every year. Your frenchies will die if you let them get too hot. Yes, that is harsh but that is less harsh than going outside and seeing your loved one dead. When you let them go outside, DO NOT FORGET ABOUT THEM. Frenchies love toddler pools and this helps give them a way to cool off if they are getting hot. If your dog overheats, do not throw extremely cold water on them as it will throw them into a shock. Take them inside to air conditioning. Cover them with cold wet towels and put a fan on them. Let them drink small amounts of cool water as they recover, but not all at once.
Monitor them until they are recovered. Also, once a dog overheats, they are more susceptible to overheating.
DO NOT LEAVE YOUR FRENCHY IN YOUR CAR EVEN WITH AIR CONDITIONER RUNNING. AND DON’T USE PLASTIC CARRIERS, THEY DON’T HAVE ENOUGH AIR VENTILATION.