The Dragon Law: A Primer On Dragons And Jurisprudence, 1744, London Wrote:The legal status of dragons has nearly always been that of a minor child legally beholden to and dependent on an adult human.  While the fact that dragons are fully sentient and sapient individuals was very quickly apparent, even to the early dragon-riders, the fact also remains that, outside of a few exceptional individual dragons, a typical dragon's abstract reasoning skills and higher order thinking processes range around those of a five- or six-year-old human child.  While dragons have their own language capable of communicating abstract concepts, much like those of corvids, prior to their integration with human society it was still extremely primitive, with even the most complex regional dialects only consisting of perhaps a thousand words.  Simply put, dragons aren't quite intelligent enough to be humanity's full intellectual partners.  Hence their legal status. 
At present, dragon-riders essentially adopt the dragon in a civil bond away from the legal trusts of the Brooderies, who corporately act as the dragons' legal guardians until and unless they are bonded to a rider.  With the bond between rider and dragon holding a legal status similar to that of a marriage or child adoption, dragon-riders are, presently, entirely responsible for the behavior of their dragon, and have obligations to the dragon in kind (food, housing, medical care, etc.). 
Ideally, it is a partnership between near-equals, where the human gives their hands and brains, and the dragon gives their wings.