Higienopolis might have the best dog amenities in all of the city. For one, the Tryp hotel is dog…read morefriendly and just around the corner, you'll find Parque Buenos Aires, one of the few parks in the city that has a fenced-in dog area where your pup can frolic and socialize with other canines.
The larger park is really lovely and while it's not massive, it's big enough to offer a needed respite from the city hustle. While not big enough to dedicate an entire jog (contrary to Ibirapuera park), it's great for an afternoon stroll and during opening hours, you'll find lovers cuddling on park benches, loners on the grass with a book, and kids on their daytime outing.
As for the dog park, it's a decent size and while there's plenty of room to run, you won't find any grass here. It's mostly a packed dirt surface, so on rainy days, this might not be the best "clean" play option. Then again, there's almost always dogs there so it's nice for a quick powwow amongst pups.