Public art is a label adopted since the late Sixties in order to identify whatever artistic experience realised out of the official frame of museums and galleries. The label is properly used when, instead of the mere public location of an artwork, a more complex process of territorial and social integration is implemented. Having its ancestors in the public monuments of XIX Century, public art was born in the United States as the source of multidisciplinary experiences involving art and architecture in the attempt of developing site specific projects. One of its main features is the unusual extension of the audience well beyond the museums and galleries club; the audience's response appears to be strictly connected with the project itself. The paper offers a critical analysis of the legislative and regulatory tools adopted by the public sector to support public art.