Through considerations about sidewalls´ billboard on the buildings of Rio overlooking beyond trade objectives the author evaluated aspects of how these information designs, nevertheless a needed service, can interfere on building finishing, on the legibility and volumetry of the city of Rio de Janeiro, within the knowledge of how important is nature to its inhabitants. A challenge in finding a cue from design´s point of view, in a clear interpretation that sidewalls´ billboard could help as a response to lack of information to people walking and/or driving in the streets. Imagining that the use of billboards on buildings under the disciplines of urbanism, architecture and information design could help to act more ideological to better understanding the use of sidewalls in Rio where living outside in open space is most important than to all other Brazilian cities and understanding that updating the law would assure actions of the state to avoid conflicts between public and private attending the needs for better intercommunication for the citizens.