author" of the house) and that you did not sign any paperwork transferring your rights.
What's at issue? You're correct about the right to shoot exterior views. We don't believe interiors, even if publicly viewable, would be covered by that exception. Unfortunately, we haven't located a case that distinguishes photos of the interior of a publicly viewable home from the exterior and that's what makes us unable to reach a more definitive conclusion. It's possible that the photographic uses of the interiors -- the real estate agent's promotion of the house sale -- would be considered permissible either under an implied license (they're essential for selling the house which we assume was everyone's goal), or possibly for purposes of fair use (the objective was to sell the house, not the images). As for further use of the photographs beyond the sale, ultimately it's going to come down to (1) whether your interiors are sufficiently original to merit copyright protection -- that is, whether the layout of the rooms goes beyond "standard configurations," (2) what elements (unprotected) are "functional elements whose design or placement is dictated by utilitarian concerns," and (3) whether the photographs of the interior reveal enough information to infringe the architectural plans or designs. Simply showing the kitchen, or bedroom, for example is unlikely by itself to constitute an infringement; you'll need to show that the combined effect of the photos is an infringement of several elements of the design. This legal article may help explain in more detail.
BTW Dept. If you're looking for more information on the law and photography we like Carolyn Wright's blog.