Unlike dogs, rabbits are not subject to breed-specific legislation, so there are no laws anywhere that single out the Mini Rex by breed. Legal questions for rabbits concern the keeping of rabbits in general rather than any particular variety, and the Mini Rex is treated exactly as any other domestic rabbit under the law.
The most significant restrictions apply at the jurisdictional level. Some places regulate or even prohibit keeping domestic rabbits as pets; the Australian state of Queensland, for example, broadly bans private rabbit ownership for ecological reasons. Such rules apply to all rabbits regardless of breed.
In the United States and most of Europe, keeping a Mini Rex as a pet is legal, but local ordinances may classify rabbits in particular ways, regulate the number kept, or impose conditions in residential zones. Owners should check municipal and county rules before acquiring a rabbit.
Because this is general guidance and not legal advice, and because rabbit-keeping rules vary widely by location and change over time, prospective owners should confirm the current law with their local animal-control or agricultural authority.