The most pet-friendly countries in the world are highlighted by the users of the world’s largest travel platform, TripAdvisor, as shown by the series of smart travel tips and strange events on the Forum Finds of the platform, which hosts the travellers’ reviews.
From TripAdvisor:

For those of us who are pet-owners, the only – ONLY! – really hard part about traveling are the times when you have to leave your dog behind. That’s probably why there are 572 responses to a TripAdvisor Forum question about the best airline to travel with pets.
There’s no one-size-fits-all answer, though: It really depends on how big your doggo is, how far you’re flying, and where you’re flying, as not all airports offer pet relief areas. Your best option might be to consider a company like Animal Airways that’s dedicated to getting your pooch from here to there safely.
Also, know that some planning is involved: At a minimum, your dog will need to be microchipped, have a pet passport, and have an up-to-date rabies vaccine. But additional regulations can vary by country – and the United Kingdom is already warning travelers that its requirements may turn into a months-long process, depending on how Brexit shakes out.
But before you figure out how to get Mr. Sniffles to the destination of your choice, you might want to consider whether or not the country will be tolerant toward your four-legged companion.
We looked to the forum, where there were more than 130 answers to a post about the most dog-friendly countries in Europe.

France was without a doubt the most frequently mentioned country.
“I live in France and work as a waitress and have 2 pugs they go everywhere with me and are almost always allowed in restaurants,” wrote hannahpixyandjack. “Where I work if we said non to our little french ladies with tou tou they would not come in.”
For some, the dog-friendly policies in France went a little too far.
“I was in a French restaurant recently,” wrote Chris S. “Couple seated facing each other, dog in Madam’s lap. Man feeding dog from his fork. I know I am too precious but it put me off my meal. I would prefer no dogs, but some places allowing dogs with a sign outside and a note to say the same on their website.”

more at tripadvisor.com