In my experience with my frenchies, my females came into their first heat between 10 months – 14 months old. After that, it is every 6-7 months. It’s recommended not to breed on first heat cycle especially if your Frenchie is under a year old. She won’t be mature enough. Among my friends in the Frenchie community, those who bred their frenchies during their first heat, on average, lost several of the puppies born.