Encontrei.
"Commercial
Commercial buildings need access to a sufficiently educated workforce, goods to sell (either shipped from industrial zones or imported), the sale of goods, taxes, and services. Ensure that there are strong supply chains so that goods and citizens can reach your commercial zones. Stores will attempt to use local industry first before importing. This can cause an issue if all of your industry is in one part of the map. Possible solutions include dispersing your industrial zones and adding transportation services, such as freight train stations and harbors, to move goods throughout your city. As commercial buildings advance in building level, they will require more workers as well as a more educated workforce. Lowering taxes can also boost commercial happiness. The Small Business Enthusiast and Big Business Benefactor policies do not have a direct impact on happiness. However, they can indirectly affect happiness by increasing the amount of traffic from increased supply deliveries.
Commercial happiness can be the most challenging to increase and many have reported issues getting it above 85%, even with 1% taxes and tax reduction policies. Part of the reason might be in the game's leisure mechanics. To your citizen and tourists, shopping at a store is a form of leisure (not marked on the leisure map) much like visiting a park or plaza. If a city is flooded with parks, citizens might be getting their leisure fulfilled there before visiting the commercial district. However, if this is the case, it is usually not extreme enough to warrant a lack of customers warning."
http://www.skylineswiki.com/Happiness